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]