The Collaborative International Dictionary of English v.0.48:

deputy \dep"u*ty\ (d[e^]p"[-u]*t[y^]), n.; pl. Deputies
   (d[e^]p"[-u]*t[i^]z). [F. d['e]put['e], fr. LL. deputatus.
   See Depute.]
   1. One appointed as the substitute of another, and empowered
      to act for him, in his name or his behalf; a substitute in
      office; a lieutenant; a representative; a delegate; a
      vicegerent; as, the deputy of a prince, of a sheriff, of a
      township, etc.
      [1913 Webster]

            There was then [in the days of Jehoshaphat] no king
            in Edom; a deputy was king.           --1 Kings
                                                  xxii. 47.
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            God's substitute,
            His deputy anointed in His sight.     --Shak.
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   Note: Deputy is used in combination with the names of various
         executive officers, to denote an assistant empowered to
         act in their name; as, deputy collector, deputy
         marshal, deputy sheriff.
         [1913 Webster]

   2. A member of the Chamber of Deputies. [France]
      [1913 Webster]

   Chamber of Deputies, one of the two branches of the French
      legislative assembly; -- formerly called Corps
      L['e]gislatif. Its members, called deputies, are elected
      by the people voting in districts.

   Syn: Substitute; representative; legate; delegate; envoy;
        agent; factor.
        [1913 Webster]