In Latin, curtus means "cut short: shortened, cut off, or incomplete."
That's where we got our English word "curt," which describes people who cut their own words short in a mean, rude way. They shorten what they say so that they barely have to speak to you at all. In other words, when people are being curt, they're being rude by speaking with as few words as possible.
Usually, we talk about curt people and their curt comments, replies, and instructions. But people can even be curt as they say zero words: they can give you a curt nod, or a curt shake of the head, or a curt gesture.
Lastly, if you know someone named Curt, Kurt, or Curtis, you might be wondering if his name is related to our word "curt." Nope! (That would be weird, right? Because who would name their baby after a mean, rude way to treat people?!) Your friend's name is probably either derived from "Conrad," a Germanic name meaning "one who advises or counsels;" or from "Cortés," a Spanish name meaning "courtly, or courteous: well-bred and polite." And "polite" is practically the opposite of our word "curt"!