Black hat

From WikiHack

A black hat is a type of hacker with a certain set of ethical values that is sometimes referred to as a cracker. One becomes a black hat hacker after having accepted the black hat 'mind set', or set of ethical values. These values often include the disregard for authority and regulation. A typical black hat would not qualm over stealing passwords, or manipulating a new employee for their personal gain.

Often times white hats look down on black hats and visa-versa due to their divergent views on ethics and morals.