(Caribbean) The lees or dregs of cane juice, used in the distillation of rum. / (Australia) Distillery effluent.

(programming, informal) A double underscore, __.

plural of dunder

Alternative form of dunderheaded

(somewhat dated) A stupid person; a dunce.

plural of dunderhead

(obsolete, nautical) ship's biscuit broken up, mixed with molasses etc. and baked

stupidity

Stupid, foolish.

dunderhead