'Trojan horse' definitions:

Definition of 'Trojan horse'

noun

A subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst [syn: fifth column, Trojan horse]

noun

A program that appears desirable but actually contains something harmful; "the contents of a trojan can be a virus or a worm"; "when he downloaded the free game it turned out to be a trojan horse" [syn: trojan, trojan horse]

noun

A large hollow wooden figure of a horse (filled with Greek soldiers) left by the Greeks outside Troy during the Trojan War [syn: Trojan Horse, Wooden Horse]

Definition of 'Trojan horse'

From: GCIDE

Trojan horse \Tro"jan horse`\, n. [from the incident described in Homer's Iliad.]
1. (Classical mythology) a large hollow wooden horse built by Greek soldiers besieging Troy during the Trojan War, and left as a "gift" when they pretended to abandon their seige. It was taken into the city by the Trojans, and Greek soldiers concealed inside came out and opened the gates to the city, enabling the capture of the city by the Greeks. [RP + PJC]
2. Hence, any thing or person which appears harmless but is designed to destroy or attack from within. It may sometimes refer to a group; -- see also fifth column. [RP + PJC]
3. (Computers) A computer program designed to evade the security precautions within a computer system and perform illicit operations, or to do malicious damage, and often designed to look like a different kind of program, such as a game, archiver, or directory lister. This term is not applied to a program that replicates itself, such as a virus. [RP + PJC]

Definition of 'trojan horse'

From: GCIDE

fifth column \fifth` col"umn\, n. [from a statement during the Spanish Civil War (1936) that the Falange had four columns of soldiers marching on the city, and a fifth column "already there" (i.e. sympathizers inside the Republican lines).]
1. a group of persons inside the battle lines of a territory engaged in a conflict, who secretly sympathize with the enemy, and who engage in espionage or sabotage; -- sometimes also referred to as a trojan horse. [RP]
2. Hence, any faction of persons within a group who secretly sympathize with an enemy, especially those who engage in activities harmful to the group; an enemy in one's midst; a group of traitors. [RP]