slam-dunk vs slam dunk

slam-dunk is not a noun while slam dunk is a noun.

Word	Noun	Adjective	Verb	Adverb
slam-dunk	No	No	Yes	No
slam dunk	Yes	No	No	No

slam-dunk (noun)	slam dunk (noun)
	a forceful dunk
	something that is a sure to occur; a foregone conclusion

slam-dunk (verb)	slam dunk (verb)
make a slam dunk; shoot a basketball in a slam dunk
make a forceful move against