Hacker
A hacker is someone who tries to get into another person's computer using computer software. The computer software could be Trojan horse programs, computer viruses, and worms. It used to mean someone who likes to do new things with computers.  The correct name for a person doing these illegal things was cracker, but many news stories used the word hacker even though it was in error. Another meaning of hacker is someone who can change or program something, like how people can change or program a Furby to say something insulting or humorous.