One who is the fattest individual among his group of friends or peers. This individual often does not believe he is fat and will accuse others of being more fat then himself. Often has a skinny body but an enormous gut.
Dear God, have you seen 120, that guy is a FAT BOI. His pre-bed beers have really caught up with him. Disgusting.
by Fatso120 August 5, 2019
 Get the Fat Boimug.
Get the Fat Boimug. by R-2 D-Tox November 16, 2005
 Get the fat boymug.
Get the fat boymug. by berry :-) January 2, 2007
 Get the fat boymug.
Get the fat boymug. Common Insult used by Bums to insult Nick Glenn. Gesture often used while saying it is Pointing and twisting wrist
by Ryan Guthrie June 10, 2003
 Get the fat boymug.
Get the fat boymug. by chapstick chad June 25, 2008
 Get the fat boymug.
Get the fat boymug. Someone who is not realy fat but acts fat by being lazy. If they are angry you can ask them if they are on a diet.
Person 1: hay whats up Fat Boy?
Fat Boy: Go away im pissed off.
Person 1: whats the matter did you start a diet?
Fat Boy: Go away im pissed off.
Person 1: whats the matter did you start a diet?
by Vince V. December 9, 2008
 Get the Fat Boymug.
Get the Fat Boymug. 