name calling vs calumny

name calling and calumny both are nouns.

Word	Noun	Adjective	Verb	Adverb
name calling	Yes	No	No	No
calumny	Yes	No	No	No

As nouns, calumny is a hypernym of name calling; that is, calumny is a word with a broader meaning than name calling:

name calling: verbal abuse; a crude substitute for argument
calumny: a false accusation of an offense or a malicious misrepresentation of someone's words or actions

Other hypernyms of name calling include calumniation, defamation, hatchet job, obloquy, traducement.

name calling (noun)	calumny (noun)
verbal abuse; a crude substitute for argument	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