Source : Webster's Revised Unabridged Dictionary (1913)

Bombastic \Bom*bas"tic\ (b[o^]m*b[.a]s"t[i^]k or
   b[u^]m*b[.a]s"t[i^]k), Bombastical \Bom*bas"tic*al\, a.
   Characterized by bombast; high-sounding; inflated. --
   {Bom*bas"tic*al*ly}, adv.

         A theatrical, bombastic, windy phraseology. --Burke.

   Syn: Turgid; tumid; pompous; grandiloquent.

Source : WordNet®

bombastically
     adv 1: in a turgid manner; "he lectured bombastically about his
            theories" [syn: {turgidly}]
     2: in a grandiose manner; "the building was bombastically
        spacious" [syn: {grandiosely}]