Also Can Be Phrased:
Keep your skeletons in your closet.
Embarrassing or incriminating secrets from your past.
To say that someone has skeletons in their closet means that they have done something in the past that they don't want other people knowing about. It does not necessarily mean that what they did was illegal or immoral, but it could. In general, it is something that would hurt their reputation. It refers to murdering someone and storing their dead body / skeletons in your closet. Saying "keep your skeletons in your closest" is a way of saying "I don't want to hear about things you've done in the past that could hurt your reputation" .. or simply "keep your secrets to yourself".
Everybody has skeletons in their closet. (meaning: Everyone has done things that they are ashamed of.)
"Did you hear that John was fired for being an ex-convict? He was in and out of jail three times!" ... "Yeah, he seemed so normal. Who had any idea he had so many skeletons in his closet?!"
I don't need to hear about your past life as a porn star. You are a good salesperson, that's all I care about. Keep your skeletons in your closet.