double-crosser vs betrayer

double-crosser and betrayer both are nouns.

Word	Noun	Adjective	Verb	Adverb
double-crosser	Yes	No	No	No
betrayer	Yes	No	No	No

As nouns, double-crosser and betrayer are synonyms defined as:

double-crosser and betrayer: a person who says one thing and does another

Other synonyms of double-crosser include double-dealer, traitor, two-timer.

double-crosser (noun)	betrayer (noun)
a person who says one thing and does another	a person who says one thing and does another
	one who reveals confidential information to the police or other authority