Source : Webster's Revised Unabridged Dictionary (1913)

Slither \Slith"er\, v. i. [Cf. G. schlittern, LG. schliddern.
   See {Slide}.]
   To slide; to glide. [Prov. Eng.]

Source : WordNet®

slither
     v : to pass or move unobtrusively or smoothly; "They slid
         through the wicket in the big gate" [syn: {slide}]