sex vs inconstant

sex is a noun but inconstant is not a noun.

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

sex (noun)	inconstant (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)	inconstant (adjective)
	likely to change frequently often without apparent or cogent reason; variable

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