drop off vs regress

drop off is not a noun while regress is a noun.

Word	Noun	Adjective	Verb	Adverb
drop off	No	No	Yes	No
regress	Yes	No	Yes	No

As verbs, regress is a hypernym of drop off; that is, regress is a word with a broader meaning than drop off:

Other hypernyms of drop off include retrograde, retrogress.

drop off (noun)	regress (noun)
	returning to a former state
	the reasoning involved when you assume the conclusion is true and reason backward to the evidence

drop off (verb)	regress (verb)
change from a waking to a sleeping state	go back to bad behavior
fall to a lower standard	get worse or fall back to a previous condition
fall or diminish	go back to a previous state
retreat	go back to a statistical means
remove (cargo, people, etc.) from and leave