Can you define both "Jewish" and "collaborate"?

I'm not trying to be flippant here. Determining who, exactly, is Jewish is a major question, as the Nazis used very specific criteria to determine if a person was Jewish, mixed-race, or "Aryan", and those designations did not always line up with the self-identification of the individuals in question. For example, I've written about so-called "Honorary Aryans" a little bit here. People like Emil Maurice, who was considered mixed-race under Nazi racial laws, did not consider himself Jewish at all.

Alternatively, there are many people who are definitely Jewish, and around whom a significant debate has occurred regarding their "collaboration". Chief example here would be any member of a so-called "Jewish Council" in one of the ghettos. Chaim Rumkowski is a good example because he was pretty-much universally hated in Lodz and was eventually beaten to death in the gas chamber just prior to his scheduled execution. But Jewish leaders installed by the Nazis faced impossible choices - how do you draw up a list of children for deportation? You know that the Germans are going to do it anyway and that it will be even more brutal if you don't help - they've proven this to you already. So what do you do? Do you make things orderly in the hope you can save some of the people? Or do you take the risk that they're going to deport you all anyway and resist outright? They are simply impossible decisions and their difficulty is revealed by the various options Jewish Council leaders took, running the gamut from overt resistance to complete compliance to suicide aimed at avoiding having to make a decision in the fist place.

Alternatively, I suspect you're thinking of folks like Stelle Kuebler, a so-called "catcher" or jew hunter (to use a better known parlance). I would be remiss if I didn't point out that she too was only helping to save her own skin, despite the obvious advantages she gained. There are loads of other examples of such individuals.

I will end only with the point that I would find it very, very unlikely to find a self-identified Jewish person who openly supported the goals of the German Nazi party without being subject to some form of coercion. Suffice it to say that I've never heard of such a person.