noun

enigma

ih-NIG-muh/ɪˈnɪɡmə/

Someone or something mysterious and difficult to understand.

The unopened stone puzzle remains an enigma with its hidden interlocking parts.

A mysterious geometric stone puzzle with hidden interlocking parts sits unopened on a table.
Etymology

Ainigma meant a dark saying or riddle. English broadened this idea from a statement concealing meaning to anything—or anyone—that an observer finds difficult to understand.

In context

Real Crime0:37
con men the most devious of all criminals charming cool and calculating they betray trust and devastate lives yet remain a complete enigma we are about to explore the mysterious world of these master criminals
The Femme Fatale Fraudster | Conmen Case Files | Real Crime

More examples

  • The cause of her sudden departure remains an enigma.
  • To his neighbors, the quiet inventor is an enigma.
  • The ocean still holds many enigmas for scientists.

Forms

enigma · enigmas

enigmatic adjective — Mysterious and difficult to understand or interpret.

Similar words

mystery
A broader term for anything unknown, unexplained, or secret.
puzzle
Emphasizes something confusing that invites an explanation or solution.
riddle
Often suggests a baffling question with a hidden answer.