In computing, a hacker is any highly skilled computer expert capable of breaking into computer systems and networks using bugs and exploits. Depending on the field of computing it has slightly different meanings, and in some contexts has controversial moral and ethical connotations. In its original sense, the term refers to a person in any one of the communities and hacker subcultures: Grey hats are hackers who are neither good nor bad, and often include people who hack 'for fun' or to 'troll'. They may both fix and exploit, though grey hats are usually associated with black hat hackers.