straightness vs sexual activity

straightness and sexual activity both are nouns.

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

As nouns, sexual activity is a hypernym of straightness; that is, sexual activity is a word with a broader meaning than straightness:

straightness: a sexual attraction to (or sexual relations with) persons of the opposite sex
sexual activity: activities associated with sexual intercourse

Other hypernyms of straightness include sex, sex activity, sexual practice.

straightness (noun)	sexual activity (noun)
a sexual attraction to (or sexual relations with) persons of the opposite sex	activities associated with sexual intercourse
freedom from crooks or curves or bends or angles
(of hair) lack of a tendency to curl
having honest intentions
trueness of course toward a goal