1. a short bar with weights at each end, used for exercise
2. a stupid person
Usage: informal; mildly offensive

Examples

• She lifted the 10-pound dumbbells during her workout.
• The gym has a complete set of dumbbells ranging from 5 to 50 pounds.
• He does bicep curls with dumbbells every morning.
• The trainer showed her proper dumbbell technique.
• Don’t be such a dumbbell – read the instructions first.
• Only a dumbbell would forget to lock the car.
• My brother can be a real dumbbell sometimes.