Skeleton in the closet (or in British English skeleton in the cupboard) is a colloquial phrase and idiom used to describe an undisclosed fact about someone which, if revealed, would damage perceptions of the person. It evokes the idea of someone having had a human corpse concealed in their home so long that all its flesh had decomposed to the bone.

It is known to have been used as a phrase as early as at least November 1816.^[1] In the most derisive of usage, murder, or significant culpability in a years-old disappearance or non-understood event (a mystery), may be implied by the phrase.

• Closeted, describing nondisclosure of sexual or gender identity
• Elephant in the room, an English metaphorical idiom for an obvious truth that is being ignored or goes unaddressed
• Milkshake Duck, an Internet meme describing someone becoming popular, only to be revealed to have a dubious history
• Nigger in the woodpile (archaic) means "some fact of considerable importance that is not disclosed—something suspicious or wrong"
• October surprise, unexpected revelations or discoveries during US presidential elections which can often alter the results of the following November election

• Phrase of the week: to have a skeleton in the cupboard – One Stop English
• The meaning and origin of the expression: A skeleton in the closet – The Phrase Finder