The word "Riddler" refers to a person who poses perplexing questions or puzzles to others as a form of intellectual challenge. Some synonyms for this term include enigma, puzzler, conundrum, brainteaser, teaser, and challenger. All of these words suggest a sense of mystery, confusion or uncertainty. An enigma is a difficult or mysterious puzzle that is hard to solve. Puzzler has a similar meaning and refers to a problem or dilemma that requires creative thinking to resolve. A conundrum is a confusing and difficult problem that is often perplexing. A brainteaser is a puzzle or problem that exercises the intellect and tests one's mental acuity. A teaser is someone who deliberately provokes or challenges by making enigmatic or cryptic remarks. Finally, the word challenger indicates someone who presents challenges or poses questions in an effort to provoke or stimulate thought.