The Collaborative International Dictionary of English v.0.48:

Fidget \Fidg"et\, v. i. [imp. & p. p. Fidgeted; p. pr. & vb.
   n. Fodgeting.] [From Fidge; cf. OE. fiken to fidget, to
   flatter, Icel. fika to hasten, Sw. fika to hunt after, AS.
   befician to deceive. Cf. Fickle.]
   To move uneasily one way and the other; to move irregularly,
   or by fits and starts. --Moore.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fidget \Fidg"et\, n.
   1. Uneasiness; restlessness. --Cowper.
      [1913 Webster]

   2. pl. A general nervous restlessness, manifested by
      incessant changes of position; dysphoria. --Dunglison.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fidget
    n 1: a feeling of agitation expressed in continual motion; "he's
         got the fidgets"; "waiting gave him a feeling of
         restlessness" [syn: fidget, fidgetiness,
         restlessness]
    v 1: move restlessly; "The child is always fidgeting in his
         seat"