enigma

Nouns

(n) something that baffles understanding and cannot be explained
- how it got out is a mystery
- it remains one of nature's secrets
closed book, mystery, secret,
(n) a difficult problem brain-teaser, conundrum, riddle,

Synonyms

closed book mystery secret brain-teaser conundrum riddle

Words of close approximity

enigma canon enigmatic enigmatical enigmatical canon enigmatically enigmatic canon