mystery
nounUK /ˈmɪstəri/
US /ˈmɪstəri/
Something that is hard to understand or explain.
The missing cake was a mystery to everyone in the house.
OTHER MEANINGS
2. A story about a crime that someone tries to solve.
She loves reading a good mystery before bed.
3. The quality of being secret or difficult to explain.
The old house was full of mystery.
4. A person or thing that people do not know much about.
The new neighbor was a bit of a mystery.