A vehicle that has been stripped of unnecessary extras, such as exhaust baffles, springs, stereo etc, so that it still functional but lacks glamour has been 'derefined'
A message that appears when you search UrbanDictionary for something that is non-existent/undefined. Occasionally after reading this message follows a sense of disappointment.
"Isn't defined yet" isn't defined yet. I guess I'll write up a definition.