Online Etymology Dictionary

factual (adj.): 1834, from fact on model of actual. Related: Factually.
faculties (n.): early 16c., "powers or properties of one's self," also "physical functions;" plural of faculty.
faculty (n.): late 14c., "ability, means, resources," from Old French faculté (14c.) "skill, accomplishment, learning," and directly from Latin facultatem (nominative facultas) "power, ability, wealth," from *facli-tat-s, from facilis (see facile).

Academic sense "branch of knowledge" probably was the earliest in English (attested in Anglo-Latin from late 12c.), on notion of "ability in knowledge." Originally each department was a faculty; the use in reference to the whole teaching staff of a college dates from 1767.
fad (n.): 1834, "hobby, pet project;" 1881 as "fashion, craze," perhaps shortened from fiddle-faddle. Or perhaps from French fadaise "trifle, nonsense," ultimately from Latin fatuus "stupid."
faddish (adj.): 1855, from fad + -ish.
fade (v.): early 14c., "lose brightness, grow pale," from Old French fader "become weak, wilt, wither," from adj. fade "pale, weak, insipid" (12c.), probably from Vulgar Latin *fatidus, some sort of blending of Latin fatuus "silly, tasteless" + vapidus "flat, flavorless." Related: Faded; fading. As a noun, from c.1300.
fader (n.): sound control device, 1931, agent noun from fade (v.).
fado (n.): popular music style of Portugal, 1902, from Latin fatum "fate, destiny" (see fate (n.)). Because the songs tell the fates of their subjects.
faeces (n.): see feces.
faerie (n.): supernatural kingdom, "Elfland," c.1300, from Old French fairie; see fairy.
faery: see faerie.
fag (v.): "to droop, decline, tire," 1520s, apparently an alteration of flag (v.) in its sense of "droop." Transitive sense of "to make (someone or something) fatigued" is first attested 1826. Related: Fagged; fagging.
fag (n.): British slang for "cigarette" (originally, especially, the butt of a smoked cigarette), 1888, probably from fag-end "extreme end, loose piece" (1610s), from fag "loose piece" (late 15c.), which is perhaps related to fag (v.).
faggot (n.1): late 13c., "bundle of twigs bound up," from Old French fagot "bundle of sticks" (13c.), of uncertain origin, probably from Italian faggotto, diminutive of Vulgar Latin *facus, from Latin fascis "bundle of wood" (see fasces).

Especially used for burning heretics (emblematic of this from 1550s), so that phrase fire and faggot was used to indicate "punishment of a heretic." Heretics who recanted were required to wear an embroidered figure of a faggot on their sleeve, as an emblem and reminder of what they deserved.
faggot (n.2): "male homosexual," 1914, American English slang (shortened form fag is from 1921), probably from earlier contemptuous term for "woman" (1590s), especially an old and unpleasant one, in reference to faggot (n.1) "bundle of sticks," as something awkward that has to be carried (cf. baggage "worthless woman," 1590s). It may also be reinforced by Yiddish faygele "homosexual," literally "little bird." It also may have roots in British public school slang fag "a junior who does certain duties for a senior" (1785), with suggestions of "catamite," from fag (v.). This also was used as a verb.
He [the prefect] used to fag me to blow the chapel organ for him. ["Boy's Own Paper," 1889]
Other obsolete senses of faggot were "man hired into military service simply to fill out the ranks at muster" (1700) and "vote manufactured for party purposes" (1817).

The oft-reprinted assertion that male homosexuals were called faggots because they were burned at the stake as punishment is an etymological urban legend. Burning was sometimes a punishment meted out to homosexuals in Christian Europe (on the suggestion of the Biblical fate of Sodom and Gomorrah), but in England, where parliament had made homosexuality a capital offense in 1533, hanging was the method prescribed. Any use of faggot in connection with public executions had long become an English historical obscurity by the time the word began to be used for "male homosexual" in 20th century American slang, whereas the contemptuous slang word for "woman" (and the other possible sources or influences listed here) was in active use. It was used in this sense in early 20c. by D.H. Lawrence and James Joyce, among others.
fagot (n.): early spelling of faggot (n.1).
Fahrenheit: 1753, named for Gabriel Daniel Fahrenheit (1686-1736), Prussian physicist who proposed the scale in 1714. An abstract surname meaning literally "experience."
faience (n.): 1714, from French faïence (16c.), probably from Fayence, French form of Faenza, city in Italy that was a noted ceramics center 16c. The city name is Latin faventia, literally "silence, meditation," perhaps a reference to a tranquil location.
fail (v.): early 13c., from Old French falir (11c., Modern French faillir) "be lacking, miss, not succeed," from Vulgar Latin *fallire, from Latin fallere "to trip, cause to fall;" figuratively "to deceive, trick, dupe, cheat, elude; fail, be lacking or defective." Related: Failed; failing. Replaced Old English abreoðan.
fail (n.): late 13c. (e.g. without fail), from Old French faile "deficiency," from falir (see fail (v.)). The Anglo-French form of the verb, failer, also came to be used as a noun, hence failure.
failing (n.): "defect, fault," 1580s, verbal noun from fail (v.).
failsafe (adj.): also fail-safe, fail safe "safe against failure," 1948, from fail (v.) + safe (adj.). Earliest reference is to furnace burners.
failure (n.): 1640s, failer, from Anglo-French failer, from Old French falir (see fail (v.)). The verb in Anglo-French used as a noun; ending altered 17c. to conform with words in -ure.
fain (adj.): Old English fægen, fagen "glad, cheerful, happy, joyful, rejoicing," from a common Germanic root (cf. Old Saxon fagan, Old Norse feginn "glad," Old High German faginon, Gothic faginon "to rejoice"), perhaps from PIE *pek- "to make pretty." As an adverb, from c.1200.
faineant (adj.): 1610s (n.), from French fainéant (16c.) "do-nothing," from fait, third person singular present tense of faire (see factitious) + néant "nothing" (cf. dolce far niente).

A French folk etymology of Old French faignant (14c.), present participle of faindre "to feign" (see feign). As an adjective, from 1855.
faint (adj.): c.1300, "wanting in courage," now mostly in faint-hearted (mid-15c.), from Old French feint "soft, weak, sluggish," past participle of feindre "hesitate, falter, be indolent, show weakness, avoid one's duty by pretending" (see feign). Sense of "weak, feeble" is early 14c. Meaning "producing a feeble impression upon the senses" is from 1650s.
faint (v.): "grow weak" (c.1300); "lose heart" (mid-14c.); see faint (adj.). Sense of "swoon" is c.1400. Related: Fainted; fainting.
faint-hearted (adj.): mid-15c., from faint (adj.) + hearted. Related: Faintheartedly; faintheartedness.
faintly (adv.): late 13c., from faint (adj.) + -ly (2).
faintness (n.): late 14c., from faint (adj.) + -ness.
fair (adj.): Old English fæger "beautiful, lovely, pleasant," from Proto-Germanic *fagraz (cf. Old Saxon fagar, Old Norse fagr, Old High German fagar "beautiful," Gothic fagrs "fit"), perhaps from PIE *pek- "to make pretty" (cf. Lithuanian puošiu "I decorate").

The meaning in reference to weather (c.1200) preserves the original sense (opposed to foul). Sense of "light-complexioned" (1550s) reflects tastes in beauty; sense of "free from bias" (mid-14c.) evolved from another early meaning, "morally pure, unblemished" (late 12c.). The sporting senses (fair ball, fair catch etc.) began in 1856. Fair play is from 1590s; fair and square is from c.1600. Fair-haired in the figurative sense of "darling, favorite" is from 1909. First record of fair-weather friends is from 1736.
fair (n.): early 14c., from Anglo-French feyre (late 13c.), from Old French feire, from Vulgar Latin *feria "holiday, market fair," from Latin feriae "religious festivals, holidays," related to festus "solemn, festive, joyous" (see feast).
fairing (n.): "piece added for streamlining purposes," 1865, from fair (v.) a ship-building word meaning "to make fair or level, to correct curvatures," from fair (adj.).
fairly (adv.): c.1400, "handsomely," from fair (adj.) + -ly (2). Meaning "impartially" is from 1670s; "somewhat" is from 1805; meaning "totally" is earlier (1590s).
fairness (n.): Old English fægernes "beauty;" see fair (adj.) + -ness. Meaning "evenhandedness" is from mid-15c.
fairway (n.): 1580s, "navigational channel of a river," from fair (adj.) + way (n.). Golfing sense is from 1910.
fairy (n.): c.1300, fairie, "enchantment, magic," from Old French faerie "land of fairies, meeting of fairies, enchantment, magic," from fae "fay," from Latin fata (plural) "the Fates," from PIE *bha- "to speak" (see fame (n.)).

As "a supernatural creature" from late 14c. [contra Tolkien; cf. "This maketh that ther been no fairyes" in "Wife of Bath's Tale"], perhaps via intermediate forms such as fairie knight "supernatural or legendary knight" (early 14c.). The diminutive winged beings so-called in children's stories seem to date from early 17c.
Yet I suspect that this flower-and-butterfly minuteness was also a product of "rationalization," which transformed the glamour of Elfland into mere finesse, and invisibility into a fragility that could hide in a cowslip or shrink behind a blade of grass. It seems to become fashionable soon after the great voyages had begun to make the world seem too narrow to hold both men and elves; when the magic land of Hy Breasail in the West had become the mere Brazils, the land of red-dye-wood. [J.R.R. Tolkien, "On Fairy-Stories," 1947]
The slang meaning "effeminate male homosexual" is first recorded 1895. Fairy ring is from 1590s. Fossil sea urchins found on the English downlands were called fairy loaves.
fairy tale (n.): "oral narrative centered on magical tests, quests, and transformations," 1749, translating French Conte de feés of Madame d'Aulnois (1698, translated into English 1699). As an adjective (also fairytale), attested by 1963.
fairyland (n.): 1580s, from fairy + land (n.).
fait accompli (n.): French, literally "an accomplished fact" (see feat).
faith (n.): mid-13c., "duty of fulfilling one's trust," from Old French feid, foi "faith, belief, trust, confidence, pledge," from Latin fides "trust, faith, confidence, reliance, credence, belief," from root of fidere "to trust," from PIE root *bheidh- (cf. Greek pistis; see bid). For sense evolution, see belief. Theological sense is from late 14c.; religions called faiths since c.1300.
faith-healer (n.): Also faith healer, attested by 1874; from faith + healer.
The power which a man's imagination has over his body to heal it or make it sick is a force which none of us is born without. The first man had it, the last one will possess it. If left to himself, a man is most likely to use only the mischievous half of the force--the half which invents imaginary ailments for him and cultivates them; and if he is one of those very wise people, he is quite likely to scoff at the beneficent half of the force and deny its existence. [Mark Twain, "Christian Science," 1907]
faithful (adj.): c.1300, "full of faith," also "firm in allegiance," from faith + -ful. Meaning "true to the facts" is from 1520s. The noun sense of "true believers" is from 1550s. Related: Faithfully; faithfulness. Old Faithful geyser named 1870 by explorer Gen. H.D. Washburn, Surveyor-General of the Montana Territory, in reference to the regularity of its outbursts.
faithless (adj.): c.1300, "unbelieving," from faith + -less. Meaning "insincere" is mid-14c. Related: Faithlessly; faithlessness.
fajita (n.): by 1979, from Spanish fajita, diminutive of faja "bandage, wrapper," from Latin fascia "band, bandage" (see fascia).
fake: attested in London criminal slang as adjective (1775), verb (1812), and noun (1851, of persons 1888), but probably older. A likely source is feague "to spruce up by artificial means," from German fegen "polish, sweep," also "to clear out, plunder" in colloquial use. "Much of our early thieves' slang is Ger. or Du., and dates from the Thirty Years' War" [Weekley]. Or it may be from Latin facere "to do." Related: Faked; fakes; faking.
faker (n.): 1885, agent noun from fake (v.).
fakir (n.): c.1600, from Arabic faqir "a poor man," from faqura "he was poor." Term for Muslim holy man who lived by begging, misapplied in 19c. English (possibly under influence of faker) to Hindu ascetics. Arabic plural form fuqara may have led to variant early English forms such as fuckiere (1630s).
falafel (n.): by 1951 as a traveler's word, not common or domestic in English until 1970s; from Arabic falafil, said to mean "crunchy."
Falange: Spanish political party founded 1933 as a fascist movement; see Falangist. Related: Falangista.