skeleton in closet
skeleton in the/(one's) closet
An embarrassing or shameful secret. Primarily heard in US. If you've got a skeleton in the closet, it will probably be exposed during this campaign. He didn't believe me when I said that I didn't have any skeletons in my closet.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
skeleton in (one's) closet
A source of shame or disgrace, as in a family, that is kept secret.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.