libelous vs calumniatory

libelous and calumniatory both are adjectives.

Word	Noun	Adjective	Verb	Adverb
libelous	No	Yes	No	No
calumniatory	No	Yes	No	No

As adjectives, libelous and calumniatory are synonyms defined as:

libelous and calumniatory: (used of statements) harmful and often untrue; tending to discredit or malign

Other synonyms of libelous include calumnious, defamatory, denigrating, denigrative, denigratory, libellous, slanderous.

libelous (adjective)	calumniatory (adjective)
(used of statements) harmful and often untrue; tending to discredit or malign	(used of statements) harmful and often untrue; tending to discredit or malign