What is the origin of the idiom "skeleton in the closet" and when to use it?

The idiom "skeleton in the closet" originated from the literal practice of hiding a deceased person's remains in a closet during times when proper burial or disposal was not possible or socially acceptable. Over time, the phrase evolved to figuratively represent a hidden or shameful secret or embarrassing truth that someone wishes to keep concealed from others. The expression is used to imply that the secret or unpleasant truth is kept hidden away, similar to how a skeleton would be concealed in a closet, and suggests that its revelation could lead to embarrassment, judgment, or negative consequences.