disparagement vs libeler

disparagement and libeler both are nouns.

Word	Noun	Adjective	Verb	Adverb
disparagement	Yes	No	No	No
libeler	Yes	No	No	No

disparagement (noun)	libeler (noun)
the act of speaking contemptuously of	one who attacks the reputation of another by slander or libel
a communication that belittles somebody or something