boastfully

from WordNet (r) 3.0 (2006)

boastfully
    adv 1: in a boastful manner; "he talked big all evening" [syn:
           {boastfully}, {vauntingly}, {big}, {large}]

from 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]