enigma
nounUK /ɪˈnɪɡmə/
US /ɪˈnɪɡmə/
Something that is very hard to understand or explain.
The strange lights in the sky were an enigma to everyone in town.
RELATED WORDS
OTHER MEANINGS
2. A person who is difficult to understand or know well.
Her quiet neighbor was an enigma to the whole street.
3. A confusing message or saying that has a hidden meaning.
The old letter was written as an enigma that took years to solve.
4. A machine used to encode secret messages during wartime.
The museum displayed an enigma used to send coded messages.