sex vs bodily function

sex and bodily function both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex	Yes	No	Yes	No
bodily function	Yes	No	No	No

As nouns, bodily function is a hypernym of sex; that is, bodily function is a word with a broader meaning than sex:

Other hypernyms of sex include activity, bodily process, body process.

sex (noun)	bodily function (noun)
activities associated with sexual intercourse	an organic process that takes place in the body
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 (verb)	bodily function (verb)
tell the sex (of young chickens)
to evoke sexual feelings