1. a short bar with a weight at each end, used typically in pairs for exercise or muscle-building.
▪ shaped like a dumbbell: "a dumbbell molecule"
2. a stupid person.informalNorth American
Word Originearly 18th century: originally denoting an apparatus similar to that used to ring a church bell (but without the bell, so noiseless or ‘dumb’); dumbbell (sense 2) (dating from the 1920s) is an extended use by association with dumb ‘stupid’.
The dumbbell, a type of free weight, is a piece of equipment used in weight training. It is usually used individually or in pairs, with one in each hand. Wikipedia
