disloyalty vs perfidy

disloyalty and perfidy both are nouns.

Word	Noun	Adjective	Verb	Adverb
disloyalty	Yes	No	No	No
perfidy	Yes	No	No	No

As nouns, perfidy is a hyponym of disloyalty; that is, perfidy is a word with a more specific, narrower meaning than disloyalty:

Other hyponyms of disloyalty include disaffection, subversiveness, traitorousness, treason, perfidiousness, treachery.

disloyalty (noun)	perfidy (noun)
the quality of being disloyal	an act of deliberate betrayal
	betrayal of a trust