DX

DX signifies that you cannot text back right now because you are currently driving. It is meant to deter texting while driving, which is dangerous and illegal in most places.

Typically, it is best never to reply to a text while operating a vehicle. However, if you must respond, you can pull over and type "dx" to communicate that you are driving and will respond when you arrive at your destination.

Remember that the recipient must know what dx means for the term to make sense. Since dx is not well known, it is probably better not to respond at all, or you should call them. You can also set your phone to automatically respond with an away message while driving.