The Collaborative International Dictionary of English v.0.48:

Hopple \Hop"ple\, v. t. [imp. & p. p. Hoppled; p. pr. & vb. n.
   Hoppling.] [From Hop; cf. Hobble.]
   1. To impede by a hopple; to tie the feet of (a horse or a
      cow) loosely together; to hamper; to hobble; as, to hopple
      an unruly or straying horse.
      [1913 Webster]

   2. Fig.: To entangle; to hamper. --Dr. H. More.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Hopple \Hop"ple\, n.
   A fetter for horses, or cattle, when turned out to graze; --
   chiefly used in the plural.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hopple
    v 1: strap the foreleg and hind leg together on each side (of a
         horse) in order to keep the legs on the same side moving in
         unison; "hobble race horses" [syn: hopple, hobble]