The meaning of a word is the meaning that most people convey using that word. In the case of "Hacker", the majority conveys the wrong meaning. Wrong in the sense, not original. To many(mostly comprising of people not directly related to), hacking is breaking into private systems, stealing passwords, making profit out of confidential details etc.
Hacker is a highly creative person who does brilliant work often concentrating in a specific field. Originally, the word "Hacker" was used in this sense in the Programming society. Eventhough it is more popular in the computer related contexts, it can be used in any discipline.
To be more strict, there is a process in becoming a hacker. There is a culture and a community that has become the backbone of computer science-Free Software Community. Here hackers are respected by all and the word "HACKER" is considered as a prestigious label.
The hacker's attitude and the subtle line characterizing "both types" of hacking is clearly presented by Brian Harvey,University of California, Berkeley at http://www.eecs.berkeley.edu/~bh/hacker.html