double cross vs perfidy

double cross and perfidy both are nouns.

Word	Noun	Adjective	Verb	Adverb
double cross	Yes	No	Yes	No
perfidy	Yes	No	No	No

As nouns, perfidy is a hypernym of double cross; that is, perfidy is a word with a broader meaning than double cross:

Other hypernyms of double cross include betrayal, treachery, treason.

double cross (noun)	perfidy (noun)
an act of betrayal	an act of deliberate betrayal
	betrayal of a trust

double cross (verb)	perfidy (verb)
betray by double-dealing