grandiloquent vs portentous

grandiloquent and portentous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
grandiloquent	No	Yes	No	No
portentous	No	Yes	No	No

As adjectives, grandiloquent and portentous are synonyms defined as:

Other synonyms of grandiloquent include overblown, pompous, pontifical.

grandiloquent (adjective)	portentous (adjective)
puffed up with vanity	puffed up with vanity
lofty in style	ominously prophetic
	of momentous or ominous significance