defame vs defamation

defame is not a noun while defamation is a noun.

Word	Noun	Adjective	Verb	Adverb
defame	No	No	Yes	No
defamation	Yes	No	No	No

defame (noun)	defamation (noun)
	an abusive attack on a person's character or good name
	a false accusation of an offense or a malicious misrepresentation of someone's words or actions

defame (verb)	defamation (verb)
charge falsely or with malicious intent; attack the good name and reputation of someone