enigma

uh-NIG-muh

meaning in plain English

Imagine a secret code you can’t crack. It’s a person or thing that just doesn’t make sense.

Think of a secret code—an enigma is that unsolvable lock in your mind.

for example

The old mansion was an enigma to the kids who tried to explore it.

If you find a puzzle box that never opens, you’ve met an enigma. It’s the kind of mystery that keeps you guessing.