A nound describing an individual, usually a man, who is known for salad tossing many men while in jail. After doing this act, they are many times f'donked unconscious, leaving them with many concussions. He is also known to be good friends of a wannemacher while in jail. Arnsby's also drive soccer mom cars, so by many are known as "mama arnsby." Often use their charm and wit to score with tabi's.
After his sixth concussion, Sam officially became the biggest arnsby in this jail.