Bombastic rhymes with:
drastic, dynastic, ecclesiastic, elastic, enthusiastic, fantastic, fantastik, gymnastic, iconoclastic, inelastic, interscholastic, monastic, onomastic, plastic, sarcastic, scholastic, stochastic, thermoplastic, unenthusiastic
drastic, dynastic, ecclesiastic, elastic, enthusiastic, fantastic, fantastik, gymnastic, iconoclastic, inelastic, interscholastic, monastic, onomastic, plastic, sarcastic, scholastic, stochastic, thermoplastic, unenthusiastic