Bright-As-Brown

1. To tell someone; Man, Woman or Child, that they're not or not being smart, in a comical manner... Being that Brown isn't a "Bright" color in the spectrum of colors.

2. To suggest that someone isn't Clever or Bright.

3. To make someone understand that they've missed the point and or punchline.

Wow! Dude, You're about as Bright-As-Brown, aren't ya!?