redundant vs redundancy

redundant is not a noun while redundancy is a noun.

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

redundant (noun)	redundancy (noun)
	repetition of an act needlessly
	the attribute of being superfluous and unneeded
	(electronics) a system design that duplicates components to provide alternatives in case one component fails
	repetition of messages to reduce the probability of errors in transmission

redundant (adjective)	redundancy (adjective)
more than is needed, desired, or required
repetition of same and identical sense with different and non-identical words