simple past tense and past participle of knuckle down

present participle of knuckle down

Stupid or inept, like a knucklehead.

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

The ball joint of the humerus in a moose's skeleton. / (slang) The noticeable shape of a man's penis when he is wearing tight clothes.

plural of moose knuckle

Resembling or characteristic of a knuckle.

Knucklelike. / Having prominent knuckles.

present participle of knuckle

plural of fuck knuckle