v.

1. To program a computer in a clever, virtuosic, and wizardly manner. Ordinary computer jockeys merely write programs; hacking is the domain of digital poets. Hacking is a subtle and arguably mystical art, equal parts wit and technical ability, that is rarely appreciated by non-hackers. See hacker.

2. To break into computer systems with malicious intent. This sense of the term is the one that is most commonly heard in the media, although sense 1 is much more faithful to its original meaning. Contrary to popular misconception, this sort of hacking rarely requires cleverness or exceptional technical ability; most so-called "black hat" hackers rely on brute force techniques or exploit known weaknesses and the incompetence of system administrators.

3. To jury-rig or improvise something inelegant but effective, usually as a temporary solution to a problem. See noun sense 2.

n.

1. A clever or elegant technical accomplishment, especially one with a playful or prankish bent. A clever routine in a computer program, especially one which uses tools for purposes other than those for which they were intended, might be considered a hack. Students at technical universities, such as MIT, are famous for performing elaborate hacks, such as disassembling the dean's car and then reassembling it inside his house, or turni...

a person who is a professional at doing some sort of service, but does crappy work.

A political appointed flunky who either doesn't want to work or who is so stupid they can't work

All the definitions here plus:
As an acronymn for Horses Ass Carrying Keys. Prison slang referring to a prison guard.

A taxi driver in any city, not necessarily New York. In NYC, hack can also refer to a livery cab driver (cabs that drive in bad neighborhoods where taxis usually don't).

1.) Short name used for "hacky sack"
2.) The goal achieved when every player within a "hack circle" kicks the hacky sack at least once without letting it touch the ground.
3.) Someone who copies, mimics, or deliberately impersonates other people, or other peoples accomplishments in search of praise.
4.) To infiltrate, destroy, reconfigure, or violate any sort of computer program, website, etc. through use of coding.
5.) To stab, slash, cut, lacerate, etc. repetitively until the object or objects are in multiple pieces.

A correctional officer (prison guard).