portentous vs pontifical

portentous is not a noun while pontifical is a noun.

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

As adjectives, portentous and pontifical are synonyms defined as:

Other synonyms of portentous include grandiloquent, overblown, pompous.

portentous (noun)	pontifical (noun)
	the vestments and other insignia of a pontiff (especially a bishop)

portentous (adjective)	pontifical (adjective)
puffed up with vanity	denoting or governed by or relating to a bishop or bishops
ominously prophetic	proceeding from or ordered by or subject to a pope or the papacy regarded as the successor of the Apostles
of momentous or ominous significance	puffed up with vanity