What is a hacker?
The term hacker is commonly used pejoratively to describe a malicious person who gains unauthorized access to computer systems with criminal intent, but is also used positively by the coding community as a term of respect for any highly skilled programmer.
What does a hacker do?
Under the computer security umbrella, hackers are divided into three subgroups: white hat, black hat, and grey hat. White hat hackers aim to fix bugs and security vulnerabilities. Black hat hackers exploit those vulnerabilities to gain unauthorized access to a system or cause unintended behavior. Grey hat hackers fall somewhere in between.
More generally, a hacker can describe a skilled enthusiast or expert in a particular field, such as art or business.