Usually meaning something along the lines of: An unauthorized user or individual who attempts to or gains access to an information system, or some information-related data.
2)Also hackers. There are really three main types of hackers, although you don't really hear about them. These are the black hat, white hat, and... well... the haxor.
some guy: dUDE I"M sooooooo a L##T HAX0r>>>>> i JUSt haxed like frikin diabl0 stof.
other guy: Yeah.. meh too.
Hacker1: Hey.. wana go hack into the pentagon and leave a message saying 'kilroy was here'?
Hacker2: No thanks, I just did that last night. How about we go out for a sandwitch and some CHIPS.
Hacker1: Maybe later, let me just update my server, I think I might be v.0.0.0.1 updates behind.