betrayer vs deceiver

betrayer and deceiver both are nouns.

Word	Noun	Adjective	Verb	Adverb
betrayer	Yes	No	No	No
deceiver	Yes	No	No	No

As nouns, deceiver is a hypernym of betrayer; that is, deceiver is a word with a broader meaning than betrayer:

Other hypernyms of betrayer include beguiler, cheat, cheater, slicker, trickster.

betrayer (noun)	deceiver (noun)
a person who says one thing and does another	someone who leads you to believe something that is not true
one who reveals confidential information to the police or other authority