portend vs augur

portend is not a noun while augur is a noun.

Word	Noun	Adjective	Verb	Adverb
portend	No	No	Yes	No
augur	Yes	No	Yes	No

As verbs, portend and augur are synonyms defined as:

portend (noun)	augur (noun)
	(ancient Rome) a religious official who interpreted omens to guide public policy

portend (verb)	augur (verb)
indicate, as with a sign or an omen	indicate, as with a sign or an omen
	predict from an omen