desertion vs apostasy

desertion and apostasy both are nouns.

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

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

Other hyponyms of desertion include exposure, tergiversation, bolt.

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