cocky

from WordNet (r) 3.0 (2006)

cocky
    adj 1: overly self-confident or self-assertive; "a very cocky
           young man"

from The Collaborative International Dictionary of English v.0.48

Cocky \Cock"y\, a. [See {Cocket}.]
   Pert. [Slang]
   [1913 Webster] Cockyolly

from Moby Thesaurus II by Grady Ward, 1.0

67 Moby Thesaurus words for "cocky":
      aggressively self-confident, arrogant, audacious, biggety, bluff,
      bold, brash, brassy, brazen, bumptious, challenging, cheeky,
      chesty, chutzpadik, cocksure, conceited, contemptuous, crusty,
      daring, defiant, defying, derisive, disdainful, disregardful,
      disrespectful, egotistical, facy, flip, flippant, fresh, gally,
      gratuitous, greatly daring, haughty, immodest, impertinent,
      impudent, insolent, know-it-all, malapert, nervy, obtrusive,
      overconfident, overwise, peacockish, peacocky, perk, perky, pert,
      prideful, proud, puffed up, regardless of consequences, rude,
      sassy, saucy, self-conceited, self-important, self-opinionated,
      smart, smart-alecky, smart-ass, stuck-up, swelled-headed,
      uncalled-for, vain, wise-ass