Definition - What does Hack mean?
To hack, in the context of computer security, is the action of performing activities on a computer system in an unauthorized manner. Computer hacking is considered an infringement of protected data and property and thus constitutes a malicious act.
Techopedia explains Hack
The U.S. has implemented a law against hacking, known as the Computer Fraud and Abuse Act. Cybercriminals can actually face prison time upon conviction, in addition to hefty fines. However, often computer hacking largely goes unreported. Large organizations may not readily admit that their secure computer networks have been hacked.
While the term hack has meant different things over time, it almost always has a negative connotation from the perspective of a non-technical person. This is despite the fact that many hackers aren't in it to do anything malicious. Some hack for the fun and challenge of it, while others do it in a professional fashion to assist organizations improve their IT security.
In addition, it is important to differentiate between the security definition of this term and the definition in the context of programming, where hack can mean a great developer, or even an inelagant solution to a problem.