ESP is a sixth sense that opperates outside of the regular five senses. That is, it is the ability to 'sense' the surrounding area beyond seeing/hearing/smelling/touching/tasting.
A person with ESP can walk into a room with their eyes closed, and they will have an automatic understanding of where everything is. It is a perfect spatial awareness. They are aware of their surroundings, even without having to look.
For example, if a person threw a ball at the back of an ESP psychic's head, they would 'sense' it coming and be able to avoid it. Or, if someone came into a room behind them they would sense it, and have an understanding of who it was. It is sort of like a 'Spidey Sense', and can seem like they have a few seconds of premonition. Really they just have an extra heightened sense.
Because of this, ESP psychics often have very good reflexes, as they are able to sense things that are happening around them right away.
Common Limitations: - Contrary to popular belief, ESP psychics do not have any foresight of the future. - ESP does not give specific details. While a person might know that something it being thrown at their head, they won't be able to tell shape or colour or size (unless they are actually looking at it). - ESP psychics only sense what is happening in their immediate area, not what is happening elsewhere.