Online Etymology Dictionary

lover-boy (n.): "boyfriend, male paramour," 1952; see lover (n.) + boy (n.).
loverly (adj.): representing in print a Cockney pronunciation of lovely (adj.), 1907; also see R.
lovesick (adj.): also love-sick, "languishing with amorous desire," 1520s, from love (n.) + sick (adj.). Related: Lovesickness.
lovesome (adj.): Old English lufsum "worthy of love," from love (n.) + -some (1). Early 13c. as "lovely," 1720 as "amorous." An old word that yet might be useful in its original sense. Related: Lovesomely; lovesomeness.
lovestruck (adj.): also love-struck, by 1762, from love (n.) + struck, from strike (v.). Love-stricken is attested from 1805.
lovey: affectionate pet name, 1731, from love (n.) + -y (3). Extended form lovey-dovey attested from 1819 (n.), 1847 as an adjective.
loving (adj.): "affectionate," early 14c. (Old English had lufende "affectionate"), verbal noun from love (v.). Loving-cup, made for several to drink from, is attested from 1808. Loving-kindness was Coverdale's word to describe God's love (Psalms lxxxix.33).
loving (n.): "love, friendship," also "sexual love," late 14c., verbal noun from love (v.).
lovingly (adv.): late 14c., from loving (adj.) + -ly (2).
low (n.1): "the ordinary sound uttered by an ox or cow" [OED], 1540s, from low (v.); ultimately imitative.
low (adv.): "near the ground, not high," c. 1200, from low (adj.). Of voices or sounds, from c. 1300.
low (n.3): the low point of anything, the minimum, 1818, originally in card games; general sense by 1911.
low (n.2): "hill, small eminence," obsolete except in place names, from Old English hlaw "hill, mound," especially "barrow," a noun related to hleonian "to lean," from PIE root *klei- "to lean." Compare Latin clivus "hill," Greek klitys "side of a hill," from the same PIE root.
low (v.): Old English hlowan "moo, make a noise like a cow," from Proto-Germanic imitative *khlo- (source also of Middle Dutch loeyen, Dutch loeien, Old Low Franconian luon, Old High German hluojen). This is perhaps identical with the imitative PIE root *kele- (2) "to shout."
low (adj.): "not high, below the usual level," late 13c., earlier lah (late 12c.), "not rising much, being near the base or ground" (of objects or persons), also "lying on the ground or in a deep place" (late 13c.). This is not found in Old English, so the word is probably from Old Norse lagr "low, low-down, short; humble," or a similar Scandinavian source (compare Swedish låg, Danish lav), from Proto-Germanic *lega- "lying flat, low" (source also of Old Frisian lech, Middle Dutch lage, Dutch laag "low," dialectal German läge "flat"), from PIE root *legh- "to lie down, lay."

In reference to sounds, "not loud," also "having a deep pitch," from c. 1300. Meaning "humble in rank" is from c. 1200; "undignified, not high in character" is from 1550s; meaning "coarse, vulgar" is from 1759. Sense of "dejected, dispirited" is attested from 1737. Of prices, from c. 1400. In geographical usage, low refers to the part of a country near the sea-shore (c. 1300), as in Low Countries "Holland, Belgium, Luxembourg" (1540s). Low German languages (1845) are so called for being spoken in the lower elevations of old Germany.
Abject, low, and mean may have essentially the same meaning, but low is more often used with respect to nature, condition, or rank: mean, to character or conduct: abject, to spirit. [Century Dictionary, 1897]
Low blow in the figurative sense (1940s) is from pugilism. To lie low is from mid-13c. as "get down so as not to be seen," 1880 in the modern slang sense "keep quiet." Low Church in 18c. English history referred to Anglicans laying little stress on church authority (1702); in 19c. it meant evangelical Anglicans.
low-budget (adj.): 1939, originally of motion pictures, "made with little expense;" from low (adj.) + budget (n.). Usually with a suggestion of low quality as a result.
low-class (adj.): 1868, from low (adj.) + class (n.). Earlier were low-born (c. 1200), low-bred (1757).
low-down (adj.): also low down, lowdown, "vulgar, far down the social scale," 1888, from low (adj.) + down (adv.). Earlier it had meant "humble" (1540s). As a noun, 1915, from the adjective, American English. Low-downer was late 19c. American English colloquial for "poor white; rude, mean person."
low-grade (adj.): 1867, originally in mining, with reference to ores, from low (adj.) + grade (n.).
low-key (adj.): 1895, from low (adj.) + key (n.1), perhaps here in the musical sense.
low-life (adj.): "disreputable, vulgar," 1794, from low (adj.) + life (n.). As a noun, also lowlife, "coarse, no-good person," from 1911. Low-lived (adj.) is attested from 1760.
low-minded (adj.): "lacking lofty or noble aspirations," c. 1740, see low (adj.)) + -minded.
low-profile (adj.): 1957, in reference to automobile wheels, from low (adj.) + profile (n.). General sense is by 1970 in American English, apparently first in reference to Nixon Administration policy of partial U.S. disengagement from burdensome commitments abroad.
low-rise (adj.): of buildings, 1957, in contrast to high-rise; see low (adv.) + rise (v.).
lowball (v.): also low-ball, "report or estimate lower," from low (adj.) + ball (n.1).
lowboy (n.): also low-boy, "chest of drawers on short legs," 1891, a hybrid from low (adj.) + French bois "wood" (see bush). Compare highboy.
lowbrow (n.): also low-brow, "person who is not intellectual," 1902, from low (adj.) + brow (n.). Said to have been coined by U.S. journalist Will Irwin (1873-1948), perhaps on the model of highbrow, which seems to be earlier. A low brow on a man as a sign of primitive qualities was common in 19c. fiction, but on a woman it was considered a mark of classical beauty.
A low brow and not a very high one is considered beautiful in woman, whereas a high brow and not a low one is the stamp of manhood. ["Medical Review," June 2, 1894]
As an adjective from 1913.
lower (adj.): Middle English lawar, lower, lougher, earlier lahre (c. 1200), comparative of lah "low" (see low (adj.)). As an adverb from 1540s. Lower-class is from 1772.
lower (v.1): c. 1600, "descend, sink, grow less or lower" (intransitive), from lower (adj.), comparative of low (adj.). Transitive meaning "let down, cause to descend" attested from 1650s. Related: Lowered; lowering. In the transitive sense "to cause to descend" the older verb was low (Middle English lahghenn, c. 1200), which continued in use into the 18c.
lower (v.2): "to look dark and menacing," also lour, from Middle English louren, luren "to frown, scowl" (early 13c.), "to lurk" (mid-15c.), from Old English *luran or from its cognates, Middle Low German luren, Middle Dutch loeren "lie in wait." The form perhaps has been assimilated to lower (v.1). Related: Lowered; lowering.
lower-case (adj.): also lowercase, 1680s, in printing, "kind of type placed in the lower case," which held small letters collectively (as opposed to capitals); see lower (adj.) + case (n.2).
lowercase (v.): "to set (text) in lower-case type," 1911, from lower-case (adj.). Related: Lowercased; lowercasing.
lowermost (adj.): 1560s, from lower (adj.) + -most. Lowermore (1660s) seems to have gone obsolete.
lowest (adj.): c. 1200, laghesst, superlative of lah "low" (see low (adj.)).
Lowestoft (n.): type of porcelain, named for a town in Suffolk where it was made from 1757. The place name is "Hlothver's Toft," from genitive singular of the proper name + Old Norse toft "a building lot," also "a deserted site."
lowing (n.): the normal bellowing of cattle, early 13c., verbal noun from low (v.).
lowland (n.): land lower than other land thereabouts, c. 1500, originally with reference to the southern and eastern regions of Scotland, from low (adj.) + land (n.). As an adjective from 1560s. Related: Lowlander.
lowliness (n.): early 15c., "meek or humble state of mind," from lowly + -ness. From 1590s as "humble state or condition."
lowly (adv.): c. 1300, "humbly, in a modest manner," from low (adj.) + -ly (2).
lowly (adj.): late 14c., "humble in feeling, not proud," from low (adj.) + -ly (1). Related: Lowlily.
lowness (n.): early 13c., from low (adj.) + -ness. Tindale and Coverdale have lowth "lowness" (with -th (2)) in Romans viii.39.
Lowrie: in Scottish, the characteristic name of the fox (c. 1500); also "crafty person, hypocrite;" see Lawrence).
lox (n.): 1934, American English, from Yiddish laks, from Middle High German lahs "salmon," from Proto-Germanic *lakhs-, from the common IE root for the fish, *laks- (source also of Lithuanian laszisza, Russian losos, Polish łosoś "salmon").
loxo-: word-forming element meaning "oblique," before vowels lox-, from Greek loxos "bent to the side, slanting, oblique," figuratively "ambiguous," a word of uncertain origin. As in loxodromics "art of oblique sailing" (1670s).
loyal (adj.): "true or faithful in allegiance," 1530s, in reference to subjects of sovereigns or governments, from Middle French loyal, from Old French loial, leal "of good quality; faithful; honorable; law-abiding; legitimate, born in wedlock," from Latin legalem, from lex "law" (see legal).

Identical with legal, which maintains the Latin form; in most uses it has displaced Middle English leal, which is an older borrowing of the French word. For the twinning, compare royal/regal. Sense development in English is feudal, via notion of "faithful in carrying out legal obligations; conformable to the laws of honor." In a general sense (of dogs, lovers, etc.), from c. 1600. As a noun meaning "those who are loyal" from 1530s (originally often in plural).
loyalism (n.): "devotion to a government or cause," 1812, from loyal + -ism.
loyalist (n.): "partisan supporter of an existing or recent government," 1680s, from loyal (adj.) + -ist. Loyolists are followers of Ignatius Loyola, founder of the Jesuits.
loyally (adv.): 1570s, from loyal + -ly (2).
loyalty (n.): c. 1400, from Old French loialte, leaute "loyalty, fidelity; legitimacy; honesty; good quality" (Modern French loyauté), from loial (see loyal). The Medieval Latin word was legalitas. The earlier Middle English form was leaute (mid-13c.), from the older French form. Loyalty oath first attested 1852.
Allegiance ... is a matter of principle, and applies especially to conduct; the oath of allegiance covers conduct only. Loyalty is a matter of both principle and sentiment, conduct and feeling; it implies enthusiasm and devotion .... [Century Dictionary, 1897]
lozenge (n.): early 14c., "plane figure having four equal sides and two acute and two obtuse angles," from Old French losenge "rhombus shape, diamond-shape" (as an ornamental motif in heraldry, etc.); "small square cake; windowpane," etc., a word used for many flat quadrilateral things (Modern French losange). It has cognates in Spanish losanje, Catalan llosange, Italian lozanga, but the origin is disputed.

Probably from a pre-Roman Celtic language, perhaps Iberian *lausa or Gaulish *lausa "flat stone" (compare Provençal lausa, Spanish losa, Catalan llosa, Portuguese lousa "slab, tombstone"). From late 14c. as "diamond-shaped cake or wafer;" specific sense "small cake or tablet (originally diamond-shaped) of medicine and sugar, etc., meant to be held in the mouth and dissolved" is from 1520s.

The related words in Continental languages often have a sense "flattery, deceit" (compare Old French losengier "to praise unduly," losenge "flattery, false praise; deceitful friendliness"), which comes probably via the notion of square flat slabs of tombstones and their fulsome epithets. Some of this made its way into Middle English via French. Chaucer uses losenger "flatterer, deceiver;" losengerye "flattery."