Dreadnought

A Dreadnaught is a type of Cardassian interstellar cruise missile. The Cardassians used them to attack Maquis worlds. One was captured and reprogrammed by B'Elanna Torres . We see her thought process at work with this device. She stuffed the missile with as much advanced technology the Maquis could get and directed it to attack a Cardassian world, including a paranoid array of "what if" instructions to keep it from being defused if it were intercepted.

Since a Dreadnaught missile has no crew, it isn't technically a starship, although it does have it's own defensive weapons to prevent interception. The Cardassians may have used them to attack Maquis targets in the DMZ without openly violating their treaty commitments.