apostasy vs desertion

apostasy and desertion both are nouns.

Word	Noun	Adjective	Verb	Adverb
apostasy	Yes	No	No	No
desertion	Yes	No	No	No

As nouns, desertion is a hypernym of apostasy; that is, desertion is a word with a broader meaning than apostasy:

Other hypernyms of apostasy include abandonment, forsaking.

apostasy (noun)	desertion (noun)
the act of abandoning a party for cause	withdrawing support or help despite allegiance or responsibility
the state of having rejected your religious beliefs for your political party or a cause (often in favor of opposing beliefs or causes)	the act of giving something up