Entries linking to uncap
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)).
c. 1400, "to put a cap on," from cap (n.); meaning "cover as with a cap" is from c. 1600. Figurative sense of "complete, consummate, bring to a climax" is from 1580s; that of "go one better, outdo, excel" is by 1821. Related: Capped; capping. To cap verses (1610s) was "to quote alternately verses each beginning with the same letter with which the last ended."
The capping of Latin verses is a common game in classical schools. No verse may be used twice, and no hesitation or delay is permitted; so that a moderate proficiency in the game supposes several thousand verses arranged in the memory alphabetically. [Century Dictionary, 1895]