Function: noun
Etymology: from the large hollow wooden horse filled with Greek soldiers and introduced within the walls of Troy by a stratagem
Date: 1837
1 : someone or something intended to defeat or subvert from within usually by deceptive means
2 : a seemingly useful computer program that contains concealed instructions which when activated perform an illicit or malicious action (as destroying data files) also : the concealed instructions of such a program ― compare VIRUS