behind someone's back

Definition

Without somebody's knowledge; secretly.

Example Sentences

• "The employees talked about their boss behind his back."
• "You will lose good karma if you say bad things behind people's backs."
• "I had never defrauded a man of a farthing, nor called him knave behind his back. But now the last rag that covered my nakedness had been torn from me. I was branded a blackleg, card-sharper, and murderer."