I’m sorry to be curt, but let’s get right to the point. You should use the adjective curt to describe a way of speaking that’s brief and blunt.

Curt often just means “terse.” In fact it comes from the Latin word curtus, which means “cut short, abridged.” But sometimes it has the added sense of being rudely short, like when you’re irritated that someone’s asking a stupid question so you give a brusk, curt response.