drop-off vs attrition

drop-off and attrition both are nouns.

Word	Noun	Adjective	Verb	Adverb
drop-off	Yes	No	No	No
attrition	Yes	No	No	No

As nouns, attrition is a hyponym of drop-off; that is, attrition is a word with a more specific, narrower meaning than drop-off:

Other hyponyms of drop-off include shrinkage, shrinking, casualty, sinking, rarefaction, dwindling, dwindling away, waning.

drop-off (noun)	attrition (noun)
a change downward	the act of rubbing together; wearing something down by friction
a steep high face of rock	a wearing down to weaken or destroy
a noticeable deterioration in performance or quality	sorrow for sin arising from fear of damnation
	the wearing down of rock particles by friction due to water or wind or ice
	erosion by friction