grandiloquent
Given to using language in a showy way by using an excessive number of difficult words to impress others; bombastic; turgid.
The American people believe that they have a free country, and we are treated to grandiloquent speeches about our flag and our reputation for freedom and enlightenment.
Where it comes from
From Middle French grandiloquent, from Latin grandiloquus, from grandis (“great, full”) + loquēns, present participle of loquor (“to speak”). Compare eloquent.
Adapted from the Wiktionary entry grandiloquent (CC BY-SA 4.0).