cancel vs rub out

cancel is a noun but rub out is not a noun.

Word	Noun	Adjective	Verb	Adverb
cancel	Yes	No	Yes	No
rub out	No	No	Yes	No

As verbs, rub out is a hyponym of cancel; that is, rub out is a word with a more specific, narrower meaning than cancel:

Other hyponyms of cancel include efface, erase, score out, wipe off, excise, expunge, scratch, strike.

cancel (noun)	rub out (noun)
a notation cancelling a previous sharp or flat

cancel (verb)	rub out (verb)
make invalid for use	remove by or as if by rubbing or erasing
remove or make invisible
declare null and void; make ineffective
postpone indefinitely or annul something that was scheduled
make up for