pleasure vs positive stimulus

pleasure and positive stimulus both are nouns.

Word	Noun	Adjective	Verb	Adverb
pleasure	Yes	No	No	No
positive stimulus	Yes	No	No	No

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

pleasure (noun)	positive stimulus (noun)
sexual gratification	a stimulus with desirable consequences
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