sure as shooting vs for certain

sure as shooting is an adjective but for certain is not an adjective.

Word	Noun	Adjective	Verb	Adverb
sure as shooting	No	Yes	No	Yes
for certain	No	No	No	Yes

As adverbs, sure as shooting and for certain are synonyms defined as:

sure as shooting and for certain: definitely or positively (`sure' is sometimes used informally for `surely')

Other synonyms of sure as shooting include certainly, for sure, sure, sure enough, surely.

sure as shooting (adjective)	for certain (adjective)
absolutely certain

sure as shooting (adverb)	for certain (adverb)
definitely or positively (`sure' is sometimes used informally for `surely')	definitely or positively (`sure' is sometimes used informally for `surely')