Online Etymology Dictionary

weary (adj.): Old English werig "tired," related to worian "to wander, totter," from West Germanic *worigaz (cf. Old Saxon worig "weary," Old High German wuorag "intoxicated"), of unknown origin.
weary (v.): Old English wergian (intransitive), gewergian (transitive), from the source of weary (adj.). Related: Wearied; wearying.
weasel (n.): Old English weosule, wesle "weasel," from Proto-Germanic *wisulon (cf. Old Norse visla, Middle Dutch wesel, Dutch wezel, Old High German wisula, German Wiesel), probably related to Proto-Germanic *wisand- "bison" (see bison), with a base sense of "stinking animal," because both animals have a foul, musky smell (cf. Latin vissio "stench"). A John Wesilheued ("John Weaselhead") turns up on the Lincolnshire Assize Rolls for 1384, but the name seems not to have endured, for some reason.
weasel (v.): "to deprive (a word or phrase) of its meaning," 1900, from weasel (n.); so used because the weasel sucks out the contents of eggs, leaving the shell intact; the sense of "extricate oneself (from a difficult place) like a weasel" is first recorded 1925; that of "to evade and equivocate" is from 1956.
weather (v.): "come through safely," 1650s, from weather (n.). Sense of "wear away by exposure" is from 1757. Related: Weathered; weathering.
weather (n.): Old English weder, from Proto-Germanic *wedran (cf. Old Saxon wedar, Old Norse veðr, Old Frisian, Middle Dutch, Dutch weder, Old High German wetar, German Wetter "storm, wind, weather"), from PIE *we-dhro-, "weather," from root *we- "to blow" (see wind (n.)). Spelling with -th- first appeared 15c., though pronunciation may be much older.

Weather-beaten is from 1520s. Under the weather "indisposed" is from 1827. Greek had words for "good weather" (aithria, eudia) and words for "storm" and "winter," but no generic word for "weather" until kairos (literally "time") began to be used as such in Byzantine times. Latin tempestas "weather" (see tempest) also originally meant "time;" and words for "time" also came to mean weather in Irish (aimsir), Serbo-Croatian (vrijeme), Polish (czas), etc.
weather-vane (n.): also weathervane, 1721, from weather (n.) + vane.
weatherman (n.): "one who observes the weather," 1901, from weather (n.) + man (n.).
weave (v.): Old English wefan "form by interlacing yarn" (class V strong verb; past tense wæf, past participle wefen), from Proto-Germanic *weban (cf. Old Norse vefa, Middle Low German, Middle Dutch, Dutch weven, Old High German weban, German weben "to weave"), from PIE *webh- "to weave;" also "to move quickly" (cf. Sanskrit ubhnati "he laces together," Persian baftan "to weave," Greek hyphe, hyphos "web," Old English webb "web").

Extended sense of "combine into a whole" is from late 14c.; meaning "go by twisting and turning" is first found 1590s. Sense in boxing is from 1818. Related: Wove; weaved; weaving.
weave (n.): "method or pattern of weaving," 1888, from weave (v.).
weaver (n.): mid-14c. (mid-13c. as a surname), agent noun from weave (v.).
web (n.): Old English webb "woven fabric," from Proto-Germanic *wabjam "fabric, web" (cf. Old Saxon webbi, Old Norse vefr, Dutch webbe, Old High German weppi, German gewebe "web"), from PIE *webh- "to weave" (see weave (v.)).

Meaning "spider's web" is first recorded early 13c. Applied to the membranes between the toes of ducks and other aquatic birds from 1570s. Internet sense is from 1992, shortened from World Wide Web (1990). Web browser, web page both also attested 1990.
Weber: surname attested from 1255; literally "weaver" (see web).
weblog (n.): by 1994; see blog.
webmaster (n.): 1993, from web in the Internet sense + master (n.).
website (n.): also web site, 1994, from web in the Internet sense + site.
webster (n.): "a weaver," Old English webbestre "a female weaver," from web (q.v.) + fem. suffix -ster. Noah Webster's dictionary first published 1828.
wed (v.): Old English weddian "to pledge, covenant to do something, marry," from Proto-Germanic *wadjojanan (cf. Old Norse veðja "to bet, wager," Old Frisian weddia "to promise," Gothic ga-wadjon "to betroth"), from PIE root *wadh- "to pledge, to redeem a pledge" (cf. Latin vas, genitive vadis "bail, security," Lithuanian vaduoti "to redeem a pledge"). Sense remained "pledge" in other Germanic languages (cf. German Wette "bet, wager"); development to "marry" is unique to English. "Originally 'make a woman one's wife by giving a pledge or earnest money', then used of either party" [Buck]. Related: Wedded; wedding.
wedding (n.): Old English weddung "state of being wed" (see wed). Meaning "ceremony of marriage" is recorded from c.1300; the usual Old English word for the ceremony was bridelope, literally "bridal run," in reference to conducting the bride to her new home. Wedding cake is recorded from 1640s; as a style of architecture, attested from 1879.
wedge (n.): Old English wecg "a wedge," from Proto-Germanic *wagjaz (cf. Old Norse veggr, Middle Dutch wegge, Dutch wig, Old High German weggi "wedge," German Weck "wedge-shaped bread roll"), of unknown origin. Wedge issue is attested from 1999.
wedge (v.): mid-15c., from wedge (n.). Related: Wedged; wedging.
wedgie (n.): 1940, "wedge-heeled shoe," from wedge (n.) + -ie. The underwear prank so called by 1970s, from the effect it gives the victim.
wedgwood (n.): type of English pottery, 1787, from Josiah Wedgwood (1730-1795), English potter.
wedlock (n.): Old English wedlac "pledge-giving, marriage vow," from wed + -lac, noun suffix meaning "actions or proceedings, practice," attested in about a dozen Old English compounds (cf. feohtlac "warfare"), but this is the only surviving example. Suffix altered by folk etymology through association with lock (n.1). Meaning "condition of being married" is recorded from early 13c.
Wednesday (n.): Old English Wodnesdæg "Woden's day," a Germanic loan-translation of Latin dies Mercurii "day of Mercury" (cf. Old Norse Oðinsdagr, Swedish Onsdag, Old Frisian Wonsdei, Middle Dutch Wudensdach). For Woden, see Odin.

Contracted pronunciation is recorded from 15c. The Odin-based name is missing in German (mittwoch, from Old High German mittwocha, literally "mid-week"), probably by influence of Gothic, which seems to have adopted a pure ecclesiastical (i.e. non-astrological) week from Greek missionaries. The Gothic model also seems to be the source of Polish środa, Russian sreda "Wednesday," literally "middle."
wee (adj.): "extremely small," mid-15c., from earlier noun use in sense of "quantity, amount" (cf. a littel wei "a little thing or amount," c.1300), from Old English wæge "weight" (see weigh). Adj. use wee bit apparently developed as parallel to such forms as a bit thing "a little thing." Wee hours is attested by 1891, from Scot. wee sma' hours (1787, Burns). Wee folk "faeries" is recorded from 1819. Weeny "tiny, small" is from 1790.
weed (n.): "plant not valued for use or beauty," Old English weod, uueod "grass, herb, weed," from Proto-Germanic *weud- (cf. Old Saxon wiod, East Frisian wiud), of unknown origin. Meaning "tobacco" is from c.1600; that of "marijuana" is from 1920s.
weed (v.): "to clear the ground of weeds," late Old English weodian, from the source of weed (n.). Related: Weeded; weeding.
weeds (n.): "garments" (now surviving, if at all, in widow's weeds), plural of archaic weed, from Old English wæd, wæde "garment, cloth," from Proto-Germanic *wedo (cf. Old Saxon wadi, Old Frisian wede "garment," Old Norse vað "cloth, texture," Old High German wat "garment"), probably from PIE *wedh-, extended form of root *au- "to weave." Archaic since early 19c.
weedy (adj.): early 15c., from weed + -y (2). Of persons, from 1852.
week (n.): Old English wice, from Proto-Germanic *wikon (cf. Old Norse vika, Old Frisian wike, Middle Dutch weke, Old High German wecha, German woche), probably originally with the sense of "a turning" or "succession" (cf. Gothic wikon "in the course of," Old Norse vika "sea-mile," originally "change of oar," Old English wican "yield, give way"), from PIE root *weik- "to bend, wind" (see vicarious).

"Meaning primarily 'change, alteration,' the word may once have denoted some earlier time division, such as the 'change of moon, half month,' ... but there is no positive evidence of this" [Buck]. No evidence of a native Germanic week before contact with the Romans. The seven-day week is ancient, probably originating from the 28-day lunar cycle, divisible into four periods of seven day, at the end of each of which the moon enters a new phase. Reinforced during the spread of Christianity by the ancient Jewish seven-day week.

As a Roman astrological convention it was borrowed by other European peoples; the Germanic tribes substituting their own deities for those of the Romans, without regard to planets. The Coligny calendar suggests a Celtic division of the month into halves; the regular Greek division of the month was into three decades; and the Romans also had a market week of nine days.
Greek planetary names [for the days of the week] ... are attested for the early centuries of our era, but their use was apparently restricted to certain circles; at any rate they never became popular. In Rome, on the other hand, the planetary names became the established popular terms, too strongly intrenched to be displaced by the eccl[esiastical] names, and spreading through most of western Europe. [Buck]
Phrase a week, as in eight days a week recorded by 1540s; see a- (1).
weekday (n.): Old English wicdæge "day of the week" (cf. Old High German wehhatag, Old Norse vikudagr). See week + day. In Middle English, any day other than Sunday.
weekend (n.): also week-end, 1630s, from week + end (n.). Originally a northern word (referring to the period from Saturday noon to Monday morning); it became general after 1878. As an adjective, "only on weekends," it is recorded from 1935. Long weekend attested from 1900; in reference to Great Britain in the period between the world wars, 1944.
weekly: mid-15c. (adv.); late 15c. (adj.), from week + -ly (2). As a noun meaning "weekly newspaper" it is recorded from 1833.
weel (n.): "deep pool," Old English wæl, cognate with West Frisian wiel, Old Low Frankish wal, Middle Dutch wael, German wehl, wehle.
ween (v.): Old English wenan "to think," from Proto-Germanic *woenijanan (cf. Old Saxon wanian, Old Norse væna, Old Frisian wena, Old High German wanen, German wähnen, Gothic wenjan "to expect, suppose, think"), from *woeniz "expectation," from PIE root *wen- "to wish, desire, strive for" (see Venus). Archaic since 17c.
weenie (n.): "frankfurter," 1906, with slang sense of "penis" following soon after, from German wienerwurst "Vienna sausage" (see wiener). Meaning "ineffectual person" is 1963; pejorative sense via penis shape, or perhaps from weenie in the sense of "small" (see wee).
weep (v.): Old English wepan "shed tears, cry" (class VII strong verb; past tense weop, past participle wopen), from Proto-Germanic *wopjan (cf. Old Norse op, Old High German wuof "shout, shouting, crying," Old Saxon wopian, Gothic wopjan "to shout, cry out, weep"), from PIE *wab- "to cry, scream" (cf. Latin vapulare "to be flogged;" Old Church Slavonic vupiti "to call," vypu "gull"). Weeping willow (cf. French saule pleureur, German trauerweide) is recorded from 1731. The tree is native to Asia; the first brought to England were imported 1748, from the Euphrates. Replaced cypress as a funerary emblem.
weepy (adj.): 1825, from weep + -y (2). Related: Weepily; weepiness.
weet (v.): 1540s, from Middle English weten, variant of witen (see wit (v.)).
weevil (n.): Old English wifel "small beetle," from Proto-Germanic *webilaz (cf. Old Saxon wibil, Old High German wibil, German Wiebel "beetle, chafer," Old Norse tordyfill "dung beetle"), cognate with Lithuanian vabalas "beetle," from PIE root *webh- "to weave," also "to move quickly" (see weave (v.)). The sense gradually narrowed to a particular kind of beetle that, in larval or adult stages, bores into plants, often destroying them.
weft (n.): Old English weft, wefta, related to wefan "to weave," from Proto-Germanic *weftaz (see weave (v.)).
wegotism (n.): 1797, from we + egotism; "an obtrusive and too frequent use of the first person plural by a speaker or writer" [OED].
Wehrmacht (n.): "the armed forces of Germany," 1935, from German Wehrmacht (name of the armed forces 1921-1945), from Wehr "defense" (see weir) + Macht "might" (see might (n.)).
weigela (n.): 1846, from the name of German physician C.E. Weigel (1748-1831).
weigh (v.): Old English wegan "find the weight of, have weight, lift, carry," from Proto-Germanic *weganan (cf. Old Saxon wegan, Old Frisian wega, Dutch wegen "to weigh," Old Norse vega, Old High German wegan "to move, carry, weigh," German wiegen "to weigh"), from PIE *wegh- "to move" (cf. Sanskrit vahati "carries, conveys," vahitram "vessel, ship;" Avestan vazaiti "he leads, draws;" Greek okhos "carriage;" Latin vehere "to carry, convey;" Old Church Slavonic vesti "to carry, convey;" Lithuanian vezu "to carry, convey;" Old Irish fecht "campaign, journey").

The original sense was of motion, which led to that of lifting, then to that of "measure the weight of." The older sense of "lift, carry" survives in the nautical phrase weigh anchor. Figurative sense of "to consider, ponder" (in reference to words, etc.) is recorded from mid-14c.
weight (n.): Old English gewiht, from Proto-Germanic *(ga)wekhtiz, *(ga)wekhtjan (cf. Old Norse vætt, Old Frisian wicht, Middle Dutch gewicht, German Gewicht), from *weg- (see weigh). The verb meaning "to load with weight" is attested from 1747; sense in statistics is recorded from 1901. To lose weight "get thinner" is recorded from 1961. Weight Watcher as a trademark name dates from 1960. To pull one's weight (1921) is from rowing.
weightage (n.): 1906, from weight + -age.
weightlessness (n.): 1884, from weight + -less + -ness.
weighty (adj.): "important, serious, grave," late 15c., from weight + -y (2).