Most people have a skeleton in their closet. Usually it's only a little skeleton ( maybe you stole a bicycle when you were a teenager, and the police arrested you. But you did not go to jail). Some people have a much bigger skeleton rattling around in their closet/wardrobe/cupboard. Some people did something really bad. Maybe they killed someone. Maybe they stole a lot of money. But it's a secret.... or only a few people know. Conversation: Sue: Do you know John Smith? He's really strange. Olga: Oh yes, I know him. Yes, he is really weird. He never leaves his house and he won't talk to anyone. Sue: I know! Never says a word. Very strange. Olga: I think he must have a skeleton in his closet! Sue: Yes, I'm sure he does. I wonder what it it? And Sue and Olga start guessing what the skeleton might be. Is John Smith a criminal? Has he done something bad in the past? What is his dark secret? Possibly John Smith just likes to live quietly, but Sue and Olga LOVE a bit of GOSSIP so they'll keep on guessing!

Sorry: Sue's last line should be, "I wonder what it IS? Didn't have my glasses on. Didn't type it correctly. Apologies.

There are so many more, Anna. Have a look at: https://en.wikipedia.org/wiki/Idiom If you have any questions, just ask!

If you mean that you want to know "skeleton in the closet" it simply means a dark or hidden secret for you .. Anything that if people know it, will become a scandal! ,, hope this help :)