fleet (v.) Look up fleet at Dictionary.com
Old English fleotan "to float, drift, flow, swim, sail," later (c.1200) "to flow," from Proto-Germanic *fleut- (cognates: Old Frisian fliata, Old Saxon fliotan "to flow," Old High German fliozzan "to float, flow," German flieszen "to flow," Old Norse fliota "to float, flow"), from PIE root *pleu- "to flow, run, swim" (see pluvial).

Meaning "to glide away like a stream, vanish imperceptibly" is from c.1200; hence "to fade, to vanish" (1570s). Related: Fleeted; fleeting.
fleeting (adj.) Look up fleeting at Dictionary.com
early 13c., "fickle, shifting, unstable," from Old English fleotende "floating, drifting," later "flying, moving swiftly," from present participle of fleotan (see fleet (v.)). Meaning "existing only briefly" is from 1560s.
Fleming (n.) Look up Fleming at Dictionary.com
Old English Flæming "native or inhabitant of Flanders," and Old Frisian Fleming, from Proto-Germanic *Flam- (source also of Medieval Latin Flamingus); see Flanders.
Flemish (adj.) Look up Flemish at Dictionary.com
early 14c., flemmysshe, probably from Old Frisian Flemische, or from Fleming + -ish.
flense (v.) Look up flense at Dictionary.com
also flench, 1814, from Danish flense, perhaps from PIE root *(s)plei- "to splice, split." Related: Flenser; flensing.
flesh (n.) Look up flesh at Dictionary.com
Old English flæsc "flesh, meat," also "near kindred" (a sense now obsolete except in phrase flesh and blood), common West and North Germanic (compare Old Frisian flesk, Middle Low German vlees, German Fleisch "flesh," Old Norse flesk "pork, bacon"), of uncertain origin, perhaps from Proto-Germanic *flaiskoz-.

Figurative use for "animal or physical nature of man" (Old English) is from the Bible, especially Paul's use of Greek sarx, which yielded sense of "sensual appetites" (c.1200). Flesh-wound is from 1670s; flesh-color, the hue of "Caucasian" skin, is first recorded 1610s, described as a tint composed of "a light pink with a little yellow" [O'Neill, "Dyeing," 1862]. An Old English poetry-word for "body" was flæsc-hama, literally "flesh-home."
flesh (v.) Look up flesh at Dictionary.com
1520s, "to render (a hunting animal) eager for prey by rewarding it with flesh from a kill," with figurative extensions, from flesh (n.). Meaning "to clothe or embody with flesh," with figurative extensions, is from 1660s. Related: Fleshed; fleshing.
fleshly (adj.) Look up fleshly at Dictionary.com
Old English flæsclic; see flesh (n.) + -ly (1).
fleshpot (n.) Look up fleshpot at Dictionary.com
from flesh (n.) + pot (n.1); literally "pot in which flesh is boiled," hence "luxuries regarded with envy," especially in fleshpots of Egypt, from Exodus xvi:3:
Whan we sat by ye Flesh pottes, and had bred ynough to eate. [Coverdale translation, 1535]
fleshy (adj.) Look up fleshy at Dictionary.com
"plump," mid-14c., from flesh (n.) + -y (2). Related: Fleshiness.
fletch (v.) Look up fletch at Dictionary.com
mid-17c., variant of fledge (v.); also see fletcher. Related: Fletched; fletching.
fletcher (n.) Look up fletcher at Dictionary.com
"arrow-maker," early 14c. (as a surname attested from 1203), from Old French flechier, from fleche "arrow," probably from Frankish, from Proto-Germanic *fleug-ika- (compare Old Low German fliuca, Middle Dutch vliecke), from PIE *pleuk-, extended form of root *pleu- "to flow" (see pluvial).
fleur-de-lis (n.) Look up fleur-de-lis at Dictionary.com
also fleur de lis, mid-14c., from Old French, literally "flower of the lily," especially borne as a heraldic device on the royal arms of France. Perhaps originally representing an iris, or the head of a scepter, or a weapon of some sort.
fleuret (n.) Look up fleuret at Dictionary.com
"small flower," 1811, from French fleurette, diminutive of fleur (see flower (n.)).
flew Look up flew at Dictionary.com
past tense of fly (v.1).
flex (v.) Look up flex at Dictionary.com
1520s, probably a back-formation from flexible. Related: Flexed; flexing.
flexibility (n.) Look up flexibility at Dictionary.com
1610s, of physical things, from French flexibilité or directly from Late Latin flexibilitatem (nominative flexibilitas), from Latin flexibilis (see flexible). Of immaterial things from 1783.
flexible (adj.) Look up flexible at Dictionary.com
early 15c., from Middle French flexible or directly from Latin flexibilis "that may be bent, pliant, flexible, yielding;" figuratively "tractable, inconstant," from flexus, past participle of flectere "to bend," of uncertain origin. Related: Flexibly.
flexion (n.) Look up flexion at Dictionary.com
c.1600, from Latin flexionem (nominative flexio) "a bending, swaying; bend, turn, curve," noun of action from past participle stem of flectere "to bend" (see flexible).
flexor (n.) Look up flexor at Dictionary.com
1610s, Modern Latin, short for musculus flexor "a bending muscle," agent noun from past participle stem of Latin flectere "to bend" (see flexible).
flextime (n.) Look up flextime at Dictionary.com
1972, translating German Gleitzeit "sliding time." See flex + time (n.).
flibbertigibbet (n.) Look up flibbertigibbet at Dictionary.com
1540s, "chattering gossip, flighty woman," probably a nonsense word meant to sound like fast talking; as the name of a devil or fiend it dates from c.1600.
flick (n.) Look up flick at Dictionary.com
mid-15c., probably imitative of a light blow with a whip. Earliest recorded use is in phrase not worth a flykke "useless." As slang for "film," it is first attested 1926, a back-formation from flicker (v.), from their flickering appearance.
flick (v.) Look up flick at Dictionary.com
1816, from flick (n.); meaning "quick turn of the wrist" is from 1897, originally in cricket. Related: Flicked; flicking.
flicker (n.) Look up flicker at Dictionary.com
1849, "wavering, unsteady light or flame;" 1857 as "a flickering," from flicker (v.).
flicker (v.) Look up flicker at Dictionary.com
Old English flicorian "to flutter, flap quickly and lightly," originally of birds. Onomatopoeic and suggestive of quick motion. Sense of "shine with a wavering light" is c.1600, but not common till 19c. Related: Flickered; flickering.
flicker (n.) Look up flicker at Dictionary.com
"woodpecker," 1808, American English, possibly echoic of bird's note, or from white spots on plumage that seem to flicker as it flits from tree to tree.
flier (n.) Look up flier at Dictionary.com
see flyer.
flight (n.1) Look up flight at Dictionary.com
"act of flying," Old English flyht "a flying, flight," from Proto-Germanic *flukhtiz (cognates: Dutch vlucht "flight of birds," Old Norse flugr, Old High German flug, German Flug "flight"), from root of *fleugan "to fly" (see fly (v.1)).

Spelling altered late 14c. from Middle English fliht (see fight (v.)). Meaning "an instance of flight" is 1785, originally of ballooning. Meaning "series of stairs between landings" is from 1703.
flight (n.2) Look up flight at Dictionary.com
"act of fleeing," from Middle English fluht (c.1200), not found in Old English, but presumed to have existed. Related to Old English fleon "flee" (see flee), and cognate with Old Saxon fluht, Old Frisian flecht "act of fleeing," Dutch vlucht, Old High German fluht, German Flucht, Old Nprse flotti, Gothic þlauhs.
flightless (adj.) Look up flightless at Dictionary.com
1875, from flight (n.1) + -less.
flighty (adj.) Look up flighty at Dictionary.com
1550s, "swift," later (1768) "fickle or frivolous," originally of skittish horses; from flight (n.1) + -y (2). Related: Flightiness.
flim-flam (n.) Look up flim-flam at Dictionary.com
also flimflam, 1530s, a contemptuous echoic construction, perhaps connected to some unrecorded dialectal word from Scandinavian (compare Old Norse flim "a lampoon"). From 1650s as a verb.
flimsy (adj.) Look up flimsy at Dictionary.com
1702, of unknown origin, perhaps a metathesis of film (n.) "gauzy covering" + -y (2). Related: Flimsily; flimsiness.
flinch (v.) Look up flinch at Dictionary.com
1570s, from obsolete flecche "to bend, flinch," probably from Old French flenchir "to bend," probably from Frankish *hlankjan or some other Germanic source (cognates: Middle High German linken, German lenken "to bend, turn, lead"), from PIE root *kleng- "to bend, turn" (see link (n.)). Related: Flinched; flinching. As a noun, from 1817.
flinders (n.) Look up flinders at Dictionary.com
mid-15c., Scottish flendris, probably related to Norwegian flindra "chip, splinter," or Dutch flenter "fragment;" ultimately from the same PIE root that produced flint.
fling (v.) Look up fling at Dictionary.com
c.1300, probably from or related to Old Norse flengja "to flog," of uncertain origin. The Middle English intransitive sense is that suggested by phrase have a fling at "make a try." An obsolete word for "streetwalker, harlot" was fling-stink (1670s). Related: Flung; flinging.
fling (n.) Look up fling at Dictionary.com
"attempt, attack," early 14c.; see fling (v.). Sense of "period of indulgence on the eve of responsibilities" first attested 1827. Meaning "vigorous dance" (associated with the Scottish Highlands) is from 1806.
flint (n.) Look up flint at Dictionary.com
Old English flint "flint, rock," common Germanic (cognates Middle Dutch vlint, Old High German flins, Danish flint), from PIE *splind- "to split, cleave," from root *(s)plei- "to splice, split" (cognates: Greek plinthos "brick, tile," Old Irish slind "brick"), perhaps a variant of *spel- (1) "to split, break off." Transferred senses were in Old English.
flintlock (n.) Look up flintlock at Dictionary.com
1680s as a type of musket-firing mechanism, from flint + lock (n.1).
flintstone (n.) Look up flintstone at Dictionary.com
early 14c., from flint + stone (n.).
flinty (adj.) Look up flinty at Dictionary.com
"hard-hearted," 1530s, from flint + -y (2). Literal sense of "resembling flint" is from 1640s. Related: Flintily; flintiness.
flip (v.) Look up flip at Dictionary.com
1590s (1520s in flip-flop), imitative or else a contraction of fillip (q.v.), which also is held to be imitative. Sense of "get excited" is first recorded 1950; flip one's lid "lose one's head, go wild" is from 1950. For flip (adj.) "glib," see flippant. Meaning "to flip a coin" (to decide something) is by 1879. As a noun by 1690s. Related: Flipped. Flipping (adj.) as euphemism for fucking is British slang first recorded 1911 in D.H. Lawrence. Flip side (of a gramophone record) is by 1949.
flip (n.) Look up flip at Dictionary.com
sailors' hot drink usually containing beer, brandy and sugar, 1690s, from flip (v.); so called from notion of it being "whipped up" or beaten.
flip-flop (n.) Look up flip-flop at Dictionary.com
also flip flop, "thong sandal," by 1972, imitative of the sound of walking in them (flip-flap had been used in various echoic senses, mostly echoic, since 1520s); sense of "complete reversal of direction" dates from 1900.
Flip-flaps, a peculiar rollicking dance indulged in by costermongers, better described as the double shuffle; originally a kind of somersault. [Hotten's Slang Dictionary, 1864]
flippancy (n.) Look up flippancy at Dictionary.com
1746, from flippant + -cy.
flippant (adj.) Look up flippant at Dictionary.com
c.1600, "talkative;" 1670s, "displaying unbecoming levity," apparently an extended form of flip (v.). Shortened form flip is attested from 1847. Related: Flippantly.
flipper (n.) Look up flipper at Dictionary.com
"limb used to swim with," 1822, agent noun from flip (v.). Sense of "rubber fin for underwater swimming" is from 1945. Slang meaning "the hand" dates from 1836. Related: Flippers.
flirt (v.) Look up flirt at Dictionary.com
1550s, originally "to turn up one's nose, sneer at," then "to rap or flick, as with the fingers" (1560s). The noun is first attested 1540s, from the verb, with the meaning "stroke of wit." It's possible that the original word was imitative, along the lines of flip (v.), but there seems to be some influence from flit, such as in the flirt sense of "to move in short, quick flights," attested from 1580s.

Meanwhile flirt (n.) had come to mean "a pert young hussey" [Johnson] by 1560s, and Shakespeare has flirt-gill (i.e. Jill) "a woman of light or loose behavior," while flirtgig was a 17c. Yorkshire dialect word for "a giddy, flighty girl." All or any of these could have fed into the main modern verbal sense of "play at courtship" (1777), which also could have grown naturally from the earlier meaning "to flit inconstantly from object to object" (1570s), perhaps influenced by Old French fleureter "talk sweet nonsense," also "to touch a thing in passing," diminutive of fleur "flower" and metaphoric of bees skimming from flower to flower.

The noun meaning "person who flirts" is from 1732. The English word also is possibly related to East Frisian flirt "a flick or light blow," and flirtje "a giddy girl." French flirter "to flirt" is a 19c. borrowing from English. Related: Flirted; flirting.
flirtation (n.) Look up flirtation at Dictionary.com
1718, noun of action from flirt (v.).