regress vs relapse

regress and relapse both are nouns.

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

As verbs, regress and relapse are synonyms defined as:

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

As verbs, relapse is a hyponym of regress; that is, relapse is a word with a more specific, narrower meaning than regress:

Other hyponyms of regress include fall back, lapse, recidivate, regress, retrogress, resile, go back, recover, recuperate.

regress (noun)	relapse (noun)
returning to a former state	a failure to maintain a higher state
the reasoning involved when you assume the conclusion is true and reason backward to the evidence

regress (verb)	relapse (verb)
go back to bad behavior	go back to bad behavior
get worse or fall back to a previous condition	deteriorate in health
go back to a previous state
go back to a statistical means