enigma

• enigma

• enigma

• Enigma

• enigma

• enigma

• enigma

• enigma

• enigma

• enigma

• enigma

• enigma

enigma

Noun

something that baffles understanding and cannot be explained; "how it got out is a mystery"; "it remains one of nature's secrets"

Synonyms:

• mystery
• enigma
• secret
• closed book

Noun

a difficult problem

Synonyms:

• riddle
• conundrum
• enigma
• brain-teaser