Hacking : The Ultimate Hacking for Beginners By Kevin Smith

Hacking is the practice of modifying the features of a system, in order to accomplish a goal outside of the creator's original purpose. The most fundamental meaning of hacking is gaining unauthorized access to data in a system or computer.

Hacking is exploiting security controls either in a technical, physical or a human-based element.  ~ Kevin Mitnick

 The person who is consistently engaging in hacking activities, and has accepted hacking as a lifestyle and philosophy of their choice, is called a hacker.