A polite way of calling someone an Idiot.
Girl: I'm so much cooler than you!

Guy: Oh, you really are a Nimbrain!
by thecoolestguyintheworld February 16, 2012
Top Definition
Another word for idiot or a weirdo or someone that has done something silly.
'Your such an nimbrain sometimes!'
by KC&GD January 27, 2012
Someone who says/does something or is stupid.

A polite was of saying Retard or Dickhead etc.
Kathryn: I'm so much cooler than you!

George: Oh dear, you really are a nimbrain!
by supercoolguy February 11, 2012
Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.