worsening vs drop-off

worsening and drop-off both are nouns.

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

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

Other hyponyms of worsening include falling off, falloff, slack, slump.

worsening (noun)	drop-off (noun)
changing something with the result that it becomes worse	a change downward
process of changing to an inferior state	a steep high face of rock
	a noticeable deterioration in performance or quality

worsening (adjective)	drop-off (adjective)
changing for the worse