Cynicism: A defense mechanism?

So I have this person in one of my classes who engages in all the discussions that come up. The comments/opinions are intelligent, and generate more discussion. But what comes to mind is how one can have so much to say about everything, and takes such a cynical and sarcastic view of the world. The phrases never fail to have a tinge of disdain, and the fluctuations in enunciation paint a perfect picture of mockery at its finest.

I must say, that this person would not be considered "generally attractive", nor "slim". So is this just a defense mechanism? To use intelligence to make up for whatever he/she feels that he/she is lacking in terms of aesthetics? And also to twist those words around and project unsatisfaction on others, in a pre-emptive way, and not get hurt/attacked?

I'm not stating that all cynics have low self esteem. There certainly are those who do it for comedy/humor, and certainly feel like they're in control of things. But those who aren't doing it for fun? Those who have become habituated to answer with a play on words, with a sharp tongue?