Idiom
at the mercy of someone and at someone's mercy
Theme: DOMINATION
under the control of someone; without defense against someone.We were left at the mercy of the arresting officer.Mrs. Franklin wanted Mr. Franklin at her mercy.
Idiom
at the mercy of someoneat the mercy of (someone/something)
unable to protect yourself from someone or something.The entire movie business is at the mercy of teenage moviegoers.If you're not legally employed, you're at your employer's mercy.