The definition of a hacker is a very skilled computer programmer who is able to gain access into secure computer systems, or a low skilled golfer or tennis player.(noun)
See hacker in Webster's New World College Dictionary
See hacker in American Heritage Dictionary 4
Origin: Perhaps from hacker, amateurish or inept golfer or tennis player (possibly from hack1)
Origin: , or perhaps from hack, practical joke, clever scheme (from dialectal hack, to embarrass, confuse, play a trick on).
Learn more about hacker