c. 1200, flitten, flytten, flutten "convey, move (a thing) from one place to another, take, carry away," also intransitive, "go away, move, migrate," from Old Norse flytja "to remove, bring," from Proto-Germanic *flutjan- "to float," from extended form of PIE root *pleu- "to flow." Intransitive sense "move lightly and swiftly" is from early 15c.; from c. 1500 as "remove from one habitation to another" (originally Northern English and Scottish)
Theire desire ... is to goe to theire newe masters eyther on a Tewsday, or on a Thursday; for ... they say Munday flitte, Neaver sitte. [Henry Best, farming & account book, 1641]
Related: Flitted; flitting. As a noun, "a flitting, a removal," from 1835.
"fly with back-and-forth motion," 1540s, from flit with frequentative suffix. Flitter-mouse (1540s) is occasionally used in English, in imitation of German fledermaus "bat," from Old High German fledaron "to bat, to flutter." Related: Flittered; flittering. As a noun, from 1892.
1550s, "to turn up one's nose, sneer at;" later "to rap or flick, as with the fingers" (1560s); "throw with a sudden movement," also "move in short, quick flights" (1580s). Perhaps imitative (compare flip (v.), also East Frisian flirt "a flick or light blow," flirtje "a giddy girl," which also might have fed into the English word), but perhaps rather from or influenced by flit (v.). Related: Flirted; flirting.
The main modern verbal sense of "play at courtship" (1777) probably developed from the noun (see flirt (n.)) but also could have grown naturally from the 16c. meaning "to flit inconstantly from object to object." To flirt a fan (1660s) was to snap it open or closed with a brisk jerk and was long considered part of the coquette's arsenal, which might have contributed to the sense shift. Or the word could have been influenced from French, where Old French fleureter meant "talk sweet nonsense," also "to touch a thing in passing," diminutive of fleur "flower" (n.) and metaphoric of bees skimming from flower to flower. French flirter "to flirt" is a 19c. borrowing from English.
Proto-Indo-European root meaning "to flow."
It forms all or part of: fletcher; fledge; flee; fleet (adj.) "swift;" fleet (n.2) "group of ships under one command;" fleet (v.) "to float, drift; flow, run;" fleeting; flight (n.1) "act of flying;" flight (n.2) "act of fleeing;" flit; float; flood; flotsam; flotilla; flow; flue; flugelhorn; fluster; flutter; fly (v.1) "move through the air with wings;" fly (n.) "winged insect;" fowl; plover; Pluto; plutocracy; pluvial; pneumo-; pneumonia; pneumonic; pulmonary.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit plavate "navigates, swims;" Greek plynein "to wash," plein "to navigate," ploein "to float, swim," plotos "floating, navigable," pyelos "trough, basin;" Latin plovere "to rain," pluvius "rainy;" Armenian luanam "I wash;" Old English flowan "to flow;" Old Church Slavonic plovo "to flow, navigate;" Lithuanian pilu, pilti "to pour out," plauju, plauti "to swim, rinse."
1880, "one who files lawsuits;" 1882, "one who argues lawsuits," agent noun from Latin litigare "to dispute, quarrel; go to court, litigate" (see litigation). Latin litigator meant "a party to a lawsuit; litigant;" it was translated in Old English as flitgern, flit-georn "one desirous of contention, a quarreler."
Middle English flashen, flasken (c. 1200), "sprinkle or splash (water, powder, etc.); to gush forth;" probably at least partly imitative (compare splash, dash), or in part from PIE *bhleu- "to swell, well up," extended form of root *bhel- (2) "to blow, swell." From c. 1400, of birds, "to dart or flit" also, of fire, "burst into flames." Some of the extended senses perhaps are from Scandinavian. Meanings "burst suddenly into view" (intransitive) and "emit or send forth suddenly" (transitive) are from 1580s. the Sense of "expose the genitals" is recorded by 1846. Related: Flashed; flashing. Flash card is from 1923.
"side of bacon," Middle English flicche (c. 1200), "side of a slaughtered animal," especially the salted and cured side of a hog, from Old English flicce "flitch of bacon, ham," from Proto-Germanic *flekkja (source also of Old Norse flikki, Middle Low German vlicke "piece of flesh"). Not immediately from flesh (n.), but perhaps from the same PIE root, *pleik- "to tear" (see flay). The Flitch of Dunmow was presented every year at Little Dunmow, in Essex, to any married couple who could prove they had lived together without quarreling for a year and a day, a custom mentioned in early references as dating to mid-13c., revived 19c.