slander vs calumniate

slander is a noun but calumniate is not a noun.

Word	Noun	Adjective	Verb	Adverb
slander	Yes	No	Yes	No
calumniate	No	No	Yes	No

As verbs, slander and calumniate are synonyms defined as:

slander and calumniate: charge falsely or with malicious intent; attack the good name and reputation of someone

Other synonyms of slander include asperse, besmirch, defame, denigrate, smear, smirch, sully.

slander (noun)	calumniate (noun)
an abusive attack on a person's character or good name
words falsely spoken that damage the reputation of another

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