- If you are incompetent you are not good at what you are doing. You might not know how to do it. You might not be able to do it.
- He is an incompetent driver, and cannot keep a car on the road.
- He died because of medicine from an incompetent doctor.
- If you are incompetent you are stupid or crazy.
- The incompetent fools ruined my whole day.
- (law) In some countries if you are incompetent the law says you are not able to decide things. This means you are not allowed to do some things but do not do need to do other things. This is often because the incompetent person is insane (crazy).
- He was found incompetent to stand trial.
- The contract is no good because she was legally incompetent when she signed it.