The Collaborative International Dictionary of English v.0.48:

Ploy \Ploy\, n.
   Sport; frolic. [Prov. Eng. & Scot.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ploy \Ploy\, v. i. [Prob. abbrev. fr. deploy.] (Mil.)
   To form a column from a line of troops on some designated
   subdivision; -- the opposite of deploy. --Wilhelm.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ploy
    n 1: an opening remark intended to secure an advantage for the
         speaker [syn: gambit, ploy]
    2: a maneuver in a game or conversation [syn: ploy, gambit,
       stratagem]