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)).
late 14c., from Old French veler, voiller (12c.), from Latin velare "to cover, veil," from velum "a cloth, covering, curtain, veil," literally "a sail" (see veil (n.)). Figurative sense of "to conceal, mask, disguise" (something immaterial) is recorded from 1530s. Related: Veiled; veiling.
Others are reading
Definitions of unveil from WordNet
remove the veil from;
Women must not unveil themselves in public in some religious societies