I've heard MBTI say that cynicism is a T trait. I don't think it is. I think that there's two kinds of cynicism, one belonging to T's and one belonging to F's. Granted, the first kind is MUCH more common, which is obviously why it's more well-known. The second one seems to be more of a secret, but I've discovered that it's very real.
Detached cynicism is what I've observed in T's. Indifferent cynicism. That's the kind of cynicism that seems to be more well-known. It's the kind of cynicism that comes about when someone (most often a T) looks at the world and all warm, cuddly, fuzzy-wuzzy ideas (or should I say 'ideals') in it that people call 'meaningful' and calmly says "nah, I don't think any of that is realistic or possible." There doesn't seem to be much, if any, emotion involved in this kind of cynicism.
And then there's the other kind of cynicism, the less common one. People don't seem to recognize the difference between this kind of cynicism and the former kind all that well. That doesn't change the fact that there're a few F's (admittedly, a MINORITY of F's, the kind of F that I always see getting mistyped as a T) who believe in it, though. It's a bitter kind of cynicism. An angry kind of cynicism. It's the kind of cynicism that is born when an F lives their life believing in an ideal (perhaps it's true love, perhaps it's eternal peace... it could be anything), and then one day experiences something that completely shatters that belief. When something like that happens it can piss off a feeler so badly to the point that said feeler goes in the complete opposite direction and learns to hate life. He/she looks at everything they see and learns to bitterly say "Fuck it. It can't be real. It can't mean anything like I used to think it did."
I know because it happened to me. I stumbled on an idea that made me come to the realization that life doesn't really mean anything at all. And I think it's inaccurate that F's are stereotyped as 'idealistic' when, in fact, they have the ability to end up straying as far from idealism as one can possibly go.