IPA: /ɪˈnɪɡmə/
KK: /ɪˈnɪɡmə/
A person or thing that is difficult to understand or explain; something that is puzzling or mysterious.
The disappearance of the ancient civilization remains an enigma to historians.
Enigma is derived from the Greek word "ainigma" (meaning riddle or puzzle), which comes from "ainiein" (meaning to speak in riddles). The word "enigma" refers to something that is puzzling or difficult to understand, akin to a riddle.
Think of a 'riddle' in Greek ('ainigma') to remember that an enigma is something puzzling or hard to understand.