libeler vs disparagement

libeler and disparagement both are nouns.

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

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