Looking for a word that describes a word with a positive connotation substituted for a negative word

So I was watching Life with Lisa Ling, the episode about sugar daddies (lol). Almost every other "sugar baby" used the word "mentor" instead of "sugar daddy". What do you call the word (with positive connotation) that is substituted for another word (essentially negative) in order to make whatever they are trying to explain/sell sound better.

In the example above, what is the word, "mentor," called?

Solution 1:

Euphemism: A mild or indirect word or expression substituted for one considered to be too harsh or blunt when referring to something unpleasant or embarrassing. - Lexico