From The Collaborative International Dictionary of English v.0.48 :
Magniloquent \Mag*nil"o*quent\, a. [L. magnus great + loquens,
-entis, p. pr. of loqui to speak. See Magnitude,
Loquacious.]
Speaking pompously; using swelling discourse; bombastic;
tumid in style; grandiloquent. -- Mag*nil"o*quent*ly, adv.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
magniloquent
adj 1: lofty in style; "he engages in so much tall talk, one
never really realizes what he is saying" [syn:
grandiloquent, magniloquent, tall]