unbend v.

prefix of reversal, deprivation, or removal (as in unhand, undo, unbutton), Old English on-, un-, from Proto-Germanic *andi- (source also of Old Saxon ant-, Old Norse and-, Dutch ont-, Old High German ant-, German ent-, Gothic and- "against"), from PIE *anti "facing opposite, near, in front of, before, against" (from PIE root *ant- "front, forehead," with derivatives meaning "in front of, before").

More or less confused with un- (1) through similarity in the notions of "negation" and "reversal;" an adjective such as unlocked might represent "not locked" (un- (1)) or the past tense of unlock (un- (2)).

Old English bendan "to bend a bow, bring into a curved state; confine with a string, fetter," causative of bindan "to bind," from Proto-Germanic base *band- "string, band" (source also of Old Norse benda "to join, strain, strive, bend"), from PIE root *bhendh- "to bind."

The meaning "curve or make crooked" (early 14c.) is via the notion of bending a bow to string it. The intransitive sense of "become curved or crooked" is from late 14c., that of "incline, turn from the straight line" is from 1510s. The figurative meaning "bow, be submissive" is from c. 1400. Cognate with band, bind, bond, and Bund. Related: Bended; bent; bending.