Top definition
A penis - particularly a penis that is curious and/or searching for something. The gorilla thumb might be particularly hairy or thick, although not necessarily. Ideally, it doesn't have a fingernail.
I'm tired. Get your gorilla thumb away from me.
by bullfrogboy October 09, 2008
Mug icon

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