In parapsychology, a Mentalist, as opposed to a psychic, is defined as someone who is believed not only to be able to read information mentally, but also to alter that information.

While a psychic may claim to observe an underlying spiritual reality and report on it, in a process known as a "psychic reading," a mentalist, by contrast, might claim the ability to manipulate that reality in order to create a different manifestation.

Stagecraft

The term "mentalist" also refers to stage magicians whose tricks feature the apparent ability to read minds, fortell the future, and see distant and hidden objects. Some of these stage mentalists, such as The Amazing Kreskin and Derren Brown, make it known to their audiences that they are performing stage tricks, while others, like Uri Geller, use these tricks to give their audiences the impression that they actually possess supernatural powers.

To be mental

Alternately, "Mentalist" is an underused word meaning one who is "mental" or mad. Featured in the UK BBC hit The Office, "Mentalist" defines the dull workers who proclaim themselves to be mad, eccentric, or generally having character. "Mentalist" can be used as a tongue-in-cheek insult for when someone is behaving oddly or wackily.

Also, the word "Mentalist" features in Steve Coogan's, Alan Partridge and has much the same meaning. "Mentalist" is also now a recognised word of this meaning, according to the new edition of the Oxford English Dictionary.