pleasure vs sexual activity

pleasure and sexual activity both are nouns.

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

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

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

pleasure (noun)	sexual activity (noun)
sexual gratification	activities associated with sexual intercourse
an activity that affords enjoyment
something or someone that provides a source of happiness
a formal expression
a fundamental feeling that is hard to define but that people desire to experience