riddle

Example:The crossword puzzle was so difficult that even the most experienced solvers took a long time to finish.

Definition:an object or game designed to stimulate the intelligence by presenting a problem to be solved.

Example:The behavior of the new employee was an enigma to everyone in the office.

Definition:a thing that is mysterious and difficult to understand or explain, often used to describe a complex or bewildering situation.

Example:The hiring manager gave a conundrum to the interviewee to assess their quick thinking.

Definition:a word puzzle or problem that one must answer by means of a clever play on words; also a puzzling question.