gender vs sexual

gender is a noun but sexual is not a noun.

Word	Noun	Adjective	Verb	Adverb
gender	Yes	No	No	No
sexual	No	Yes	No	No

gender (noun)	sexual (noun)
the properties that distinguish organisms on the basis of their reproductive roles
a grammatical category in inflected languages governing the agreement between nouns and pronouns and adjectives; in some languages it is quite arbitrary but in Indo-European languages it is usually based on sex or animateness

gender (adjective)	sexual (adjective)
	having or involving sex
	of or relating to or characterized by sexuality
	involved in a sexual relationship