1. 
[syn: puzzle, puzzler, mystifier, teaser]
The Collaborative International Dictionary of English v.0.48:
Puzzler \Puz"zler\, n.
   One who, or that which, puzzles or perplexes.
   [1913 Webster]
         Hebrew, the general puzzler of old heads. --Brome.
   [1913 Webster]
WordNet (r) 3.0 (2006):
puzzler
    n 1: a particularly baffling problem that is said to have a
         correct solution; "he loved to solve chessmate puzzles";
         "that's a real puzzler" [syn: puzzle, puzzler,
         mystifier, teaser]
Moby Thesaurus II by Grady Ward, 1.0:
28 Moby Thesaurus words for "puzzler":
   Chinese puzzle, baffling problem, brain twister, crossword puzzle,
   crux, enigma, enigmatic question, floorer, jigsaw puzzle, knot,
   knotty point, mind-boggler, mystery, nut to crack,
   perplexed question, perplexity, poser, problem, puzzle, puzzlement,
   question, question mark, sixty-four dollar question, sticker,
   stumper, tough proposition, vexed question, why