Someone who is doing/saying something idiotic or foolish

1. Blue Monday is the most depressing day of the year, calculated by Dr. Cliff Arnall, a researcher at the University of Cardiff's Center for Lifelong Learning.
Factors used to calculate the date included weather conditions, debt level, time since Christmas, time since failing our New Year's resolutions, low motivation and feeling the need to take action.

In 2005 the date was calculated as January 24th, in 2006 it was January 23rd, and in 2007 it was January 22nd.

2. A song by the hard rock band Orgy from their album Candy Ass.

To review an image on the LCD screen of a digital camera after taking a photograph. In common usage among press photographers. The act was dubbed chimping after photographers were caught making monkey-like noises when they reviewed a good shot in their cameras.

see Dubya

A dumbass person

Somebody who's freakin' out and needs to chill. Can be used as a verb, noun or adjective.

Can be used as either a noun or a verb. As a noun, chimp describes someone who departs from a public house or club early to return to one's domicile. This could be for a variety of reasons: too ripped up to continue drinking, being ejected by bouncers (a corollary of being ripped) or being under the thumb. The verbal form is used to describe this act of baling out early: thus 'to chimp out'.