defection vs desertion

defection and desertion both are nouns.

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

As nouns, defection and desertion are synonyms defined as:

defection and desertion: withdrawing support or help despite allegiance or responsibility

Other synonyms of defection include abandonment.

defection (noun)	desertion (noun)
withdrawing support or help despite allegiance or responsibility	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