The word curt, describing someone who speaks in a rather rude and also brief kind of a way, is, unsurprisingly, linked to the Latin word curtus, which means cut short or mutilated.
The interesting thing is that the first synonym for the word curt in my Collins dictionary is blunt.
Thing Not To Be Today: curt. Or, indeed, blunt.
(Yes, I know, so many people are idiots: but they're never going to improve unless you explain things nicely, are they?
Mind you, if you get it wrong and end up being patronising then that's not going to help anyone, either.)