skeleton in the closet

1. A potentially embarrassing secret: “Before nominating the new judge, the committee asked him if he had any skeletons in the closet.”

Idioms and Phrases

A shameful secret, as in Both her parents were alcoholics; that was the skeleton in her closet . This metaphoric term alludes to a murder victim long concealed in a closet, possibly based on some true incident that is now forgotten. [Early 1800s]