From Longman Dictionary of Contemporary Englishhackerhack‧er /ˈhækə $ -ər/ noun [countable] informalTD someone who secretly uses or changes the information in other people’s computer systems A hacker had managed to get into the system. —hacking noun [uncountable] the threat of hacking and computer viruses
Examples from the Corpus
hacker• Hackers broke into the Pentagon's security system last night.• It turned out that a hacker had been masquerading as Weiss online.• A hacker, apparently based in St Petersburg, had been accessing Microsoft's internal systems for a number of days.• Computing becomes an end in itself as the fledgling hacker gets sucked into the loop between the human and the computer.• Originally, heroes at Apple were the hackers and engineers who created the products.• Even if the only thing hackers are stealing is free telephone service.• I should like to know whether there are any occupational diseases to which hackers are prone.From Longman Business Dictionaryhackerhack‧er /ˈhækə-ər/ noun [countable] COMPUTING someone who secretly reaches information on someone else’s computer system so that they can look at, use, or change itIntercepting messages on the Internet is easy for a smart hacker. 