[originally, someone who makes furniture with an axe]
- A person who enjoys exploring the details of programmable systems and how to stretch their capabilities, as opposed to most users, who prefer to learn only the minimum necessary.
- One who programs enthusiastically (even obsessively) or who enjoys programming rather than just theorising about programming.
- A person who is good at programming quickly.
- An expert at a particular program, or one who frequently does work using IT or on IT; as in ‘a Unix hacker’.
- An expert or enthusiast of any kind (an astronomy hacker, for example).
- One who enjoys the intellectual challenge of creatively overcoming or circumventing limitations.
- [deprecated] A malicious meddler who tries to discover sensitive information by poking around.
- Hence password hacker, network hacker.
- The correct term for this malicious meddler is a cracker.
from: The Jargon File, MIT
Watch MrC in a speech made at 'Think Computer Science' in 2015 where he tells us why 'Hacker is not a Dirty Word'