hacker:
(plural: ‘hackers‘; for the right pronunciation, please click here)

Max Ray Butler, one of notorious hackers, USA
a computer specialist (usually a teenager) who can open others’ computer files by (hacking) breaking into the secret codes of their systems (also called ‘crackers‘ in the present usage);
a computer specialist or a person who has too much interest in computers; a computer buff; a computer hobbyist;
a person who likes very much and follows a particular sport or game;
(less commonly and also ‘hackie’) a taxi driver,

a weekend golf hacker, hacking at the ball
James is a computer hacker; he knows everything about computers and can make computers do anything for him!
Kate is the youngest hacker in our city who had hacked into two hundred company sites and gathered private and personal information of those company customers before she was arrested last month for trying to sell the information to other companies.
Before the word hacker got into the computer arena, taxicab drivers in some places were called hackers, hacks or hackies, but now as this word carries a negative connotations with it, nobody likes to be called a hacker.
