megalophonous
Strident or pompous in expression; vociferous.
literary, rare
Let the megalophonous grasshopper sound a blast and summon hither the perfunctory and circumforaneous TumbleBug, to the end that excavations may be made and learning gather new treasures.
Loud.
literary, rare
The doors were closed against further admissions at 1 A. M., but not before a dozen callow youths had got in, their heads already buzzing with wine and their voices megalophonous with song.
Where it comes from
Either an adapted borrowing of Ancient Greek μεγαλόφωνος (megalóphōnos) + -ous, or independently from megalo- + -phonous.
Adapted from the Wiktionary entry megalophonous (CC BY-SA 4.0).