Synonyms for Puzzler:

n.

headache, mare, a tall order, necessity, chore, the impossible, task, burden, struggle, conundrum, riddle, show, enigma, perplexity, mystery, the elephant in the room. •mystery (noun)
conundrum, enigma, perplexity, teaser, riddle, puzzle.
•puzzler (noun)
puzzle, teaser, mystifier.

Other synonyms:

conundrum, enigma. riddle. mystery, perplexity. •Other relevant words:
riddle, conundrum, perplexity, mystery, enigma.

Usage examples for puzzler

1. This, too, was a puzzler – The Heart of the Range by William Patterson White