set down vs drop off

set down and drop off both are verbs.

Word	Noun	Adjective	Verb	Adverb
set down	No	No	Yes	No
drop off	No	No	Yes	No

As verbs, set down and drop off are synonyms defined as:

Other synonyms of set down include discharge, drop, put down, unload.

set down (verb)	drop off (verb)
put down in writing; of texts, musical compositions, etc.	change from a waking to a sleeping state
remove (cargo, people, etc.) from and leave	fall to a lower standard
put or settle into a position	fall or diminish
cause to sit or seat or be in a settled position or place	retreat
go ashore	remove (cargo, people, etc.) from and leave
reach or come to rest