Stupid or inept, like a knucklehead.

The state or condition of being knuckleheaded; foolishness or ineptitude.

Resembling or characteristic of a knuckle.

present participle of knuckleball

simple past tense and past participle of knuckleball

Third-person singular simple present indicative form of knucklewalk

plural of knucklewalker

To walk quadrupedally with the forelimbs holding the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles.

present participle of knucklewalk

simple past tense and past participle of knucklewalk