lapse vs relapse

lapse and relapse both are nouns.

Word	Noun	Adjective	Verb	Adverb
lapse	Yes	No	Yes	No
relapse	Yes	No	Yes	No

As nouns, lapse and relapse are synonyms defined as:

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

As verbs, lapse and relapse are synonyms defined as:

Other synonyms of lapse include fall back, recidivate, regress, retrogress.

lapse (noun)	relapse (noun)
a mistake resulting from inattention	a failure to maintain a higher state
a failure to maintain a higher state
a break or intermission in the occurrence of something

lapse (verb)	relapse (verb)
go back to bad behavior	go back to bad behavior
drop to a lower level, as in one's morals or standards	deteriorate in health
end, at least for a long time
for time to move forward
pass into a specified state or condition; sink into
let slip