sexual activity vs posterior

sexual activity and posterior both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual activity	Yes	No	No	No
posterior	Yes	Yes	No	No

sexual activity (noun)	posterior (noun)
activities associated with sexual intercourse	the fleshy part of the human body that you sit on
	a tooth situated at the back of the mouth

sexual activity (adjective)	posterior (adjective)
	located at or near or behind a part or near the end of a structure
	coming at a subsequent time or stage