sex vs fellatio

sex and fellatio both are nouns.

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

sex (noun)	fellatio (noun)
activities associated with sexual intercourse	oral stimulation of the penis
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)	fellatio (verb)
tell the sex (of young chickens)
to evoke sexual feelings