hacker
person who uses technical knowledge to achieve a goal within a computerized system by non-standard means
security hacker
someone who explores methods for breaching defenses and exploiting weaknesses in a computer system or network
cracker
someone who cracks digital security
hacker
person who modifies software or hardware of technical equipment, mainly their own private computer system, out of personal interest
grey hat
may refer to an individual who acts in a variety of IT-related areas; hacker
Cult of the Dead Cow
American hacker organization