The Collaborative International Dictionary of English v.0.48:

Wriggle \Wrig"gle\, v. i. [imp. & p. p. Wriggled; p. pr. & vb.
   n. Wriggling.] [Freq. of wrig, probably from OE. wrikken to
   move to and fro; cf. LG. wriggeln, D. wrikken, Sw. vricka,
   Dan. vrikke.]
   To move the body to and fro with short, writhing motions,
   like a worm; to squirm; to twist uneasily or quickly about.
   [1913 Webster]

         Both he and successors would often wriggle in their
         seats,
         as long as the cushion lasted.           --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wriggle \Wrig"gle\, v. t.
   To move with short, quick contortions; to move by twisting
   and squirming; like a worm.
   [1913 Webster]

         Covetousness will wriggle itself out at a small hole.
                                                  --Fuller.
   [1913 Webster]

         Wriggling his body to recover
         His seat, and cast his right leg over.   --Hudibras.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wriggle \Wrig"gle\, a.
   Wriggling; frisky; pliant; flexible. [Obs.] "Their wriggle
   tails." --Spenser.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wriggle \Wrig"gle\, n.
   Act of wriggling; a short or quick writhing motion or
   contortion.
   [Webster 1913 Suppl.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

wriggle
    n 1: the act of wiggling [syn: wiggle, wriggle, squirm]
    v 1: to move in a twisting or contorted motion, (especially when
         struggling); "The prisoner writhed in discomfort"; "The
         child tried to wriggle free from his aunt's embrace" [syn:
         writhe, wrestle, wriggle, worm, squirm, twist]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "wriggle":
   fidget, flip out, flow, flutter, freak out on, get high on, glide,
   glow, go pitapat, have the fidgets, have the shakes, heave, jerk,
   ooze, palpitate, pant, quake, quaver, quiver, shake, shiver, slide,
   slip, squiggle, squirm, swell, swell with emotion, thrill,
   thrill to, throb, tingle, tingle with excitement, toss,
   toss and turn, tremble, tumble, turn on to, twist and turn, twitch,
   twitter, wag, waggle, wiggle, worm, writhe