1570s, apparently a nasalized form of obsolete Middle English flecche "to bend, flinch," which probably is from Old French flechir "to bend" (Modern French fléchir), also flechier "to bend, turn aside, flinch," which probably are from Frankish *hlankjan or some other Germanic source, from Proto-Germanic *hlinc- (source also of Middle High German linken, German lenken "to bend, turn, lead"), from PIE root *kleng- "to bend, turn" (see link (n.)). There were nasalized form of the word in Old French as well (flenchir "to bend; give ground, retreat"). Related: Flinched; flinching. As a noun, "the action of flinching," from 1817.
updated on November 24, 2014