redundant vs extra

redundant is not a noun while extra is a noun.

Word	Noun	Adjective	Verb	Adverb
redundant	No	Yes	No	No
extra	Yes	Yes	No	Yes

As adjectives, redundant and extra are synonyms defined as:

Other synonyms of redundant include excess, spare, supererogatory, superfluous, supernumerary, surplus.

redundant (noun)	extra (noun)
	something additional of the same kind
	an additional edition of a newspaper (usually to report a crisis)
	a minor actor in crowd scenes

redundant (adjective)	extra (adjective)
more than is needed, desired, or required	further or added
repetition of same and identical sense with different and non-identical words	more than is needed, desired, or required
	added to a regular schedule

redundant (adverb)	extra (adverb)
	unusually or exceptionally