nincompoop

don't be such a nincompoop when making decisions.

he acted like a nincompoop during the meeting.

calling her a nincompoop was unkind.

she felt like a nincompoop for forgetting his birthday.

sometimes i feel like a nincompoop for not understanding the instructions.

he made a nincompoop of himself by tripping on stage.

don't be a nincompoop; read the instructions carefully.

she laughed at her friend for being a nincompoop.

it's a nincompoop move to ignore the warnings.

he called himself a nincompoop after failing the test.