run afoul vs breach

run afoul is not a noun while breach is a noun.

Word	Noun	Adjective	Verb	Adverb
run afoul	No	No	Yes	No
breach	Yes	No	Yes	No

As verbs, breach is a hypernym of run afoul; that is, breach is a word with a broader meaning than run afoul:

Other hypernyms of run afoul include break, go against, infract, offend, transgress, violate.

run afoul (noun)	breach (noun)
	a failure to perform some promised act or obligation
	a personal or social separation (as between opposing factions)
	an opening (especially a gap in a dike or fortification)

run afoul (verb)	breach (verb)
go against, as of rules and laws	make an opening or gap in
	act in disregard of laws, rules, contracts, or promises