go back on vs promise

go back on is not a noun while promise is a noun.

Word	Noun	Adjective	Verb	Adverb
go back on	No	No	Yes	No
promise	Yes	No	Yes	No

go back on (noun)	promise (noun)
	grounds for feeling hopeful about the future
	a verbal commitment by one person to another agreeing to do (or not to do) something in the future

go back on (verb)	promise (verb)
fail to fulfill a promise or obligation	make a promise or commitment
	promise to undertake or give
	make a prediction about; tell in advance
	give grounds for expectations