The Collaborative International Dictionary of English v.0.48:

Waddle \Wad"dle\, v. i. [imp. & p. p. Waddled; p. pr. & vb. n.
   Waddling.] [Freq. of wade; cf. AS. w[ae]dlian to beg, from
   wadan to go. See Wade.]
   To walk with short steps, swaying the body from one side to
   the other, like a duck or very fat person; to move clumsily
   and totteringly along; to toddle; to stumble; as, a child
   waddles when he begins to walk; a goose waddles. --Shak.
   [1913 Webster]

         She drawls her words, and waddles in her pace. --Young.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Waddle \Wad"dle\, v. t.
   To trample or tread down, as high grass, by walking through
   it. [R.] --Drayton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

waddle
    n 1: walking with short steps and the weight tilting from one
         foot to the other; "ducks walk with a waddle"
    v 1: walk unsteadily; "small children toddle" [syn: toddle,
         coggle, totter, dodder, paddle, waddle]