What is hacking?

Hacking is the act of breaking in to a computersystem and is a criminal offence under the computer misuse.

Answer:

The really simple definition of hacking: is gaining an unauthorized access to a computer system.

Answer:

Hacking, for the most part is about learning how a system works and how to make it do things it wasn't designed to do, or you haven't got the privileges to do.

Answer:

Usually people instantly think hacking is gaining access into a server, taking a copy of a credit card database or some other attack. This is one end of the spectrum. The other end (the most common end), is perhaps best reflected in wireless routers. A hacker buys a Linksys router, realises that the hardware is extraordinarily limited, and then flashes it and installs new firmware and after a few more tweaks is able to have a cheap router doing the job of a very expensive cisco router.