lapsing vs backsliding

lapsing and backsliding both are nouns.

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

As nouns, lapsing and backsliding are synonyms defined as:

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

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