- noun (written as Trojan Horse)a program inserted into a system by a hacker that will perform a harmless function while copying information held in a classified file into a file with a low priority, which the hacker can then access without the authorised user’s knowledge
- A program which appears to be useful and/or harmless, but which actually causes serious harm to a computer it is run on. A Trojan house may be utilized, for instance, to collect private information, such as passwords, or to destroy data. Unlike viruses, Trojan horses do not replicate themselves. Also called Trojan. A popular misnomer for this term is Trojan virus.