Distrait means "preoccupied with worry." If you can't concentrate on the hot gossip your friend is sharing with you because you can't stop thinking about what your mom is going to say about the window you accidentally broke, you're distrait.
The adjective distrait comes from the Latin word distrahere, meaning “pull apart,” which describes what happens to your thoughts when you are distrait. It looks and sounds like distract, another word that has to do with the ability to pay attention. But while anything can make you feel distracted — a noise outside your window, a phone call that comes when you are supposed to be studying — distrait always has to do with worry and anxiety.