sex vs sexy

sex is a noun but sexy is not a noun.

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

sex (noun)	sexy (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

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

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