Top Definition
An imaginary (yet vital) loose part hanging from underneath an unsuspecting motorist's car. Alerting unsuspecting motorists about said item is of supreme importance. Mission accomplished when unsuspecting motorist pulls over and gets out to see whats wrong with his car.
Driver 1: (while pointing at undercarriage) "Hey Sir, your Fister saster caster unit is out"
Driver 2: "What"?
Driver 1: "Your fister saster, the caster unit, it's out" (still pointing)
Driver 2: "oh really?!? oh, um ok" (pulls into rite-aid parking lot)
Driver 1 then laughs laughs laughs all the way to work.
by Mergeman August 05, 2008

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt