The Collaborative International Dictionary of English v.0.48:

Wabble \Wab"ble\ (w[o^]b"b'l), v. i. [Cf. Prov. G. wabbeln to
   wabble, and E. whap. Cf. Quaver.]
   To move staggeringly or unsteadily from one side to the
   other; to vacillate; to move the manner of a rotating disk
   when the axis of rotation is inclined to that of the disk; --
   said of a turning or whirling body; as, a top wabbles; a buzz
   saw wabbles.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wabble \Wab"ble\, n.
   A hobbling, unequal motion, as of a wheel unevenly hung; a
   staggering to and fro.
   [1913 Webster]