The Collaborative International Dictionary of English v.0.48:

Boastful \Boast"ful\, a.
   Given to, or full of, boasting; inclined to boast; vaunting;
   vainglorious; self-praising. -- Boast"ful*ly, adv. --
   Boast"ful*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boastful
    adj 1: exhibiting self-importance; "big talk" [syn: boastful,
           braggart(a), bragging(a), braggy, big, cock-a-
           hoop, crowing, self-aggrandizing, self-
           aggrandising]