A simpleton, usually who drives a beat up lifted pick-up truck preferably Cheverolet, Ford, Dodge or GMC because gas is so much cheaper than rice, with extra big ties and wheels such as Super Swampers. In order to reach the full nirt-nirt potential, usually factory exhaust (or whats left of it) is modified or afro-engineered with larger pipes and wire coathangers to create a throaty-rumbling that is sure to offend any other drivers on the road with their windows down. Nirt-nirts may or may not have the following charactaristics: underaged girlfriends; tend to take breaks from having jobs; chewing-tobacco habit; enjoy Natural Light reeb; smacking women (but only when they don't listen) attending mud-bogs in manuer feilds; throwing roosters; taking food to the lighthouse keeper; heated arguments with other nirt-nirt buddies about which truck is better/tougher/faster, or which can go through more shit... Ford? Chevy? or Dodge?
Nirt-nirt #1: "Line that bitch up and we'll see how good your Fucked-Over-Rebuilt-Dodge is against my Chevy. I have 38" Super Swampers, yours are only 33's!"
Nirt-nirt #2: "Awe fuck you, 38's are only good if your truck had the balls to spin them!"