Top Definition
To think so intensely, that sleep cannot be acheived. People who are unable to fall asleep because they are of superior intellect & can't turn off their minds. A blending of the words brainiac and insomniac.
Sally was still awake at 2AM because she is a brainsomniac.
by The Brilliant Blonde March 17, 2010
Free Daily Email

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

Emails are sent from We'll never spam you.