dunderhead

don't be such a dunderhead; think before you act.

he called me a dunderhead for forgetting the meeting.

sometimes i feel like a dunderhead when i make silly mistakes.

she acted like a dunderhead during the presentation.

my brother can be a real dunderhead at times.

don't be a dunderhead; just ask for help!

he felt like a dunderhead for missing the obvious clues.

being a dunderhead won't get you far in life.

she often jokes about being a dunderhead when it comes to math.

calling someone a dunderhead can hurt their feelings.