'dumbbell' definitions:

Definition of 'dumbbell'

(from WordNet)
noun
An exercising weight; two spheres connected by a short bar that serves as a handle
noun
An ignorant or foolish person [syn: dumbbell, dummy, dope, boob, booby, pinhead]

Definition of 'dumbbell'

From: GCIDE
  • dumbbell \dumb"bell`\, dumb-bell \dumb"-bell`\, n. An exercising weight, consisting of two spheres or spheroids, connected by a short bar for a handle; used (often in pairs) for gymnastic exercise. [1913 Webster]
  • 2. an ignorant or foolish person.
  • Syn: dummy, dope, boob, booby, pinhead. [WordNet 1.5]