portentous vs pompous

portentous and pompous both are adjectives.

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

As adjectives, portentous and pompous are synonyms defined as:

Other synonyms of portentous include grandiloquent, overblown, pontifical.

portentous (adjective)	pompous (adjective)
puffed up with vanity	characterized by pomp and ceremony and stately display
ominously prophetic	puffed up with vanity
of momentous or ominous significance