(adjective - slang) - a person, thing or event that is
disappointing,
frustrating, unappealing, a bummer, a real downer; something that is not classic. Such as: "That movie was diet."
(Note: this
definition, though inadvertently, was taken from Coca-Cola's choice of branding for its regular soda, Coca-Cola Classic, and it's Diet Coke. See example.)
synonyms: nasty, terrible, awful, lame.
antonym: classic, as such: "classic is good, diet is bad"; fly; sweet
Daytona Beach, FL; summer, 1987:
During the unloading of a delivery truck, most of a stack of Coca-Cola soda cans crashed to the floor
in the back of a
grocery store after being hit by an arriving, full palette of other goods. One store worker, trying to save surviving cases of cans from the carnage, took a lot of soda spray to his clothes, eyeglasses and skin.
A coworker, just arriving on the scene and comprehending the accident, joked, "Wow, that was classic."
"Nope," replied the worker, looking at his wet, sticky work clothes. "It was diet. It was definitely not classic."
Realizing the
double entendre, a slang term was born (at least in those parts).