grandiloquist

Someone who is grandiloquent, especially one who makes a living by giving lectures.

Neither do the public concern themselves how he adjuts his oratorical visage to help by his powers of face; nor heed, whether as a grandiloquist he harangues to us out of the clouds; or as a ventriloquist, out of his belly.[…]he unwittingly exhibits the real dimensions of his capacity, for, good man, he lets out, that in his grand speech on Irish Repeal, he figured as a grandiloquist! But Sir Robert must shine as something grand, be it only as a grandiloquist.

Nevertheless, when it came to personal practice and example, nothing can be more manifest than that the great current of his sympathies was with the refining grandiloquists who flourished in the time of the Charleses.

grandiloquent; bombastic.

The language is a little too grandiloquist perhaps, but the subject bears it out.

The contempt of that large-minded gentleman (Mr. Roscoe Conkling) is so wilting; his haughty disdain, his grandiloquist swell, his majestic, supereminent, overpowering, turkey-gobbler strut has been so crushing to myself and all the members of this house that I know it was an act of the greatest temerity for me to venture upon a controversy with him.