Top Definition
This term describes a situation in which a male, generally younger, recieves an excitation of the genitals due to no discernable circumstance. e.g. in class before an oral presentation or standing up on a public bus.
"I hope this No Purpose Boner (NPB) goes down before my chemistry presentation" - yin
by RashadMcCants January 04, 2006

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