per square inch

sometimes used in paintball

A guy who says offensive things and decides whether he was joking based on the reaction of people around him.

Common abbrevation for Psionic Energy,
it can also be used as the name of a catagory of skills, often called Psionics.

PSI: A black and white Siberian Husky with one brown eye and one blue eye. The most extravagant Siberian Husky in the United States. He's very loyal, protective, and very athletic. The best friend you will ever have.

Knows his surroundings, capable of saluting, shaking your hand, giving you a high five and knows how to speak.

The letter in the Greek Alphabet that comes after chi and before omega.

Pounds per square inch.

If used in the form "That person has a high PSI". It is a sexual reference saying there ass or another part of the body where a penis can be inserted is capable of taking alot of pressure, or quite a hard pounding. Can also reference to the largest penis they can fit in their ass before the pressure gets to high and rips it.

unbelievably sexy, near orgasmic lower back