call off vs cancel

call off is not a noun while cancel is a noun.

Word	Noun	Adjective	Verb	Adverb
call off	No	No	Yes	No
cancel	Yes	No	Yes	No

As verbs, call off and cancel are synonyms defined as:

call off and cancel: postpone indefinitely or annul something that was scheduled

Other synonyms of call off include scratch, scrub.

call off (noun)	cancel (noun)
	a notation cancelling a previous sharp or flat

call off (verb)	cancel (verb)
give the calls (to the dancers) for a square dance	make invalid for use
postpone indefinitely or annul something that was scheduled	remove or make invisible
	declare null and void; make ineffective
	postpone indefinitely or annul something that was scheduled
	make up for