UPDATE: Images don’t seem to be working, so they’re also linked
Streetfighter: A race-tuned sportbike that has been stripped of fairings and other bodywork, detuned for more torque (potentially at the cost of horsepower), and given a more upright riding position. Examples: Triumph Speed Triple (below) and Street Triple, Ducati Streetfighter, Suzuki Bandit, Honda CB1000R (NOT to be confused with CBR1000, the liter sportbike), etc.
Chopper: Not to be confused with “cruiser,” a chopper is typically a cruiser that, somewhat analogously to the sportbike->streetfighter transformation, is stripped of unnecessary parts and bodywork, and, most importantly, had its frame modified (usually “chopped”) to lower the seat and dramatically increase rake and trail. Historically, choppers are custom-built one-off bikes, though their rise in popularity has given way to some chopper-focused manufacturers. Example below (Big Dog “Wolf”):
Fender eliminator: Many sportbikes ship with gnarly plastic fenders. Fender eliminator kits range from a screwdriver to a replacement bit of bodywork meant to create an attractive and fenderless rear end. Example below (Suzuki GSX-R600):
Hanging off: The practice used by racers on the track of moving their bodyweight towards the inside of a corner, hanging closer to the ground than the bike carrying them. Example (John Hopkins, Rizla Suzuki team):