0 a person or thing that joins and deceives a group or organization in order to attack it from the inside:
Older supporters have accused the new leadership of being a Trojan horse that will try to destroy the party from the inside.
It's easier than you think to inadvertently download a malicious Trojan horse.
1 someone or something in a system, organization, etc. that at first seems to be helpful, but then causes harm:
2 a type of software, usually downloaded from the internet, that seems to be an ordinary program but that can destroy, or allow someone to steal, data: