Definition & Meaning of "[grease] {one's} [hand|palm]"

What is the origin of the idiom "grease one's hand" and when to use it?

The idiom "grease one's hand" likely originated from the practice of bribing or corrupting someone in authority by offering them money, which would be concealed in the hand or palm as a discreet transaction. The word "grease" in this context suggests the use of money to make a transaction or deal more smoothly or easily. This phrase is used to describe the act of giving someone money or a bribe, typically in a secretive or underhanded manner, to influence their decisions, secure special treatment, or gain an unfair advantage. It often carries a negative connotation, implying dishonesty or corruption.