While at work today, I found myself tossing around various concepts, free-associating a bit, and eventually the process turned to analogies. I'm sure most of you understand the concept: A is to B as C is to D. Well, I managed to come up with one to which I either don't have the answer, or I can't bring it to mind.
? is to hedonist as sadist is to masochist.
For the life of me, I simply can't come up with a word that fits under that question mark. The closest I come is Heinlein's "water-brother", from Stranger in a Strange Land, but that concept is far too loose for what I have in mind.
By preference, I'd prefer to have the word in English; failing that, in some human language - non-fictional. Is this truly such a rare concept among human beings that a species which cannot help verbalizing any idea it can conceive doesn't have a word for it? Or have I simply not encountered such a word?