grease the palm

To bribe someone discreetly or surreptitiously, as by slipping money into their palm. Every political lobbyist knows you've got to grease the palm now and then to get things done the way you want. Greasing the palm was the only way I could stop my brother from telling Mom that I had a party while she was away. A: "How are we going to get a table without a reservation?" B: "Don't worry, I'll talk to the hostess and grease the palm."