puzzle
US /ˈpʌz.əl/
UK /ˈpʌz.əl/

1.
rompecabezas, acertijo
a game, toy, or problem designed to test ingenuity or knowledge.
:
•
She spent hours trying to solve the jigsaw puzzle.
Pasó horas tratando de resolver el rompecabezas.
•
The crossword puzzle in the newspaper was very challenging.
El crucigrama del periódico era muy desafiante.
2.
misterio, incógnita
a person or thing that is difficult to understand or explain.
:
•
His sudden disappearance remains a complete puzzle.
Su repentina desaparición sigue siendo un completo misterio.
•
The human mind is a complex puzzle.
La mente humana es un complejo rompecabezas.