1. Individuals who possess IQ's under the standard cut off line of 70. 2. a person who is so retarded looking that their head is shaped like that of your office's communal water cooler. 3. That 50 year old guy with thick glasses who lives down the street in his eighty year old parent's house and runs with limp wrists.
Water cooler heads must often wear adult diapers because they have yet to master the elegant art of toiletry.