[pea.cock] n [ME pecok, fr. pe- (fr. OE pea peafowl, fr. L pavon-, pavo peacock) + cok cock] (14c) 1: a male peafowl distinguished by a crest of upright plumules and by greatly elongated loosely webbed upper tail coverts which are mostly tipped with ocellated spots and can be erected and spread at will in a fan shimmering with iridescent color; broadly: peafowl
2: one making a proud display of himself: show-off -- pea.cock.ish adj -- pea.cocky adj
[2]peacock vi (1586): show off