sexy vs sex

sexy is not a noun while sex is a noun.

Word	Noun	Adjective	Verb	Adverb
sexy	No	Yes	No	No
sex	Yes	No	Yes	No

sexy (noun)	sex (noun)
	activities associated with sexual intercourse
	the properties that distinguish organisms on the basis of their reproductive roles
	all of the feelings resulting from the urge to gratify sexual impulses
	either of the two categories (male or female) into which most organisms are divided

sexy (adjective)	sex (adjective)
marked by or tending to arouse sexual desire or interest
stimulating sexual desire

sexy (verb)	sex (verb)
	tell the sex (of young chickens)
	to evoke sexual feelings