cancel vs call off

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

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

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

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

Other synonyms of cancel include scratch, scrub.

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

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