relapsing vs backsliding

relapsing and backsliding both are nouns.

Word	Noun	Adjective	Verb	Adverb
relapsing	Yes	No	No	No
backsliding	Yes	No	No	No

As nouns, relapsing and backsliding are synonyms defined as:

Other synonyms of relapsing include lapse, lapsing, relapse, reversion, reverting.

relapsing (noun)	backsliding (noun)
a failure to maintain a higher state	a failure to maintain a higher state