Knuckleheaded act is a term used to describe an action that is foolish or silly. The crossword solution for this term is 'NOOGIE, ' which is a slang term for a type of headlock where the person's head is held in place and the knuckles are used to lightly tap the top of the head. This type of headlock is usually done in a playful manner, but can be seen as a sign of disrespect or aggression depending on the context.