flirt vs sexual activity

flirt and sexual activity both are nouns.

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

flirt (noun)	sexual activity (noun)
playful behavior intended to arouse sexual interest	activities associated with sexual intercourse
a seductive woman who uses her sex appeal to exploit men

flirt (verb)	sexual activity (verb)
talk or behave amorously, without serious intentions
behave carelessly or indifferently