"You can help correct the misunderstanding simply by making a distinction between security breaking and hacking—by using the term "cracking" for security breaking. The people who do it are "crackers". Some of them may also be hackers, just as some of them may be chess players or golfers; most of them are not."
A very bad player. Somewhat synonymous with "duffer" in that they both apply to poor players. But "duffer" is sometimes used to denote weaker players in general, while "hacker" is often applied to a single golfer as an insult. Hacker is a little bit stronger than duffer, in other words.
Well, in golf, being a hacker is an insult. From http://golf.about.com/cs/golfterms/g/bldef_hacker.htm
Hacker:
A very bad player. Somewhat synonymous with "duffer" in that they both apply to poor players. But "duffer" is sometimes used to denote weaker players in general, while "hacker" is often applied to a single golfer as an insult. Hacker is a little bit stronger than duffer, in other words.