1670s, "a false show, assumed appearance;" 1680s as "a pretended blow, movement made to deceive an opponent as to the object of an attack," from French feinte "a feint, sham, fabrication, pretense," abstract noun from Old French feint "false, deceitful; sham, artificial; weak, faint, lazy, indolent" (13c.), originally fem. past participle of feindre "pretend, shirk," from Latin fingere "to touch, handle; devise; fabricate, alter, change" (from PIE root *dheigh- "to form, build").
Borrowed c. 1300 as adjective ("deceitful," also "enfeebled; lacking in courage;" see feint (v.)), but long obsolete in that sense except as a trade spelling of faint among stationers and paper-makers. Also as a noun in Middle English with senses "false-heartedness" (early 14c.), "bodily weakness" (c. 1400).
c. 1300, feinten, "to deceive, pretend" (obsolete), also "become feeble or exhausted; to lack spirit or courage," from Middle English feint (adj.) "feigned, false, counterfeit" and directly from Old French feint "false, deceitful; weak, lazy," past participle of feindre "to hesitate, falter; lack courage; feign, pretend, simulate," from Latin fingere "to touch, handle; devise; fabricate, alter, change" (from PIE root *dheigh- "to form, build"). Sense of "make a sham attack, make a pretended blow" is attested by 1833, from the noun (1680s as "a feigned attack"). Related: Feinted; feinting.