The Collaborative International Dictionary of English v.0.48:

Diddler \Did"dler\, n.
   A cheat. [Colloq.]
   [1913 Webster]

   Jeremy Diddler, a character in a play by James Kenney,
      entitled "Raising the wind." The name is applied to any
      needy, tricky, constant borrower; a confidence man.
      [1913 Webster]