sexual activity vs ring of color

sexual activity and ring of color both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual activity	Yes	No	No	No
ring of color	Yes	No	No	No

sexual activity (noun)	ring of color (noun)
activities associated with sexual intercourse	small circular area such as that around the human nipple or an inflamed area around a pimple or insect bite