Source : Webster's Revised Unabridged Dictionary (1913)

Stealthy \Stealth"y\, a. [Compar. {Stealthier}; superl.
   {Stealthiest}.]
   Done by stealth; accomplished clandestinely; unperceived;
   secret; furtive; sly.

         [Withered murder] with his stealthy pace, . . . Moves
         like a ghost.                            --Shak.

Source : WordNet®

stealthy
     adj : marked by quiet and caution and secrecy; taking pains to
           avoid being observed; "a furtive manner"; "a lurking
           prowler"; "a sneak attack"; "stealthy footsteps"; "a
           surreptitious glance at his watch"; "someone skulking
           in the shadows" [syn: {furtive}, {lurking}, {skulking},
            {sneak(a)}, {sneaky}, {surreptitious}]
     [also: {stealthiest}, {stealthier}]

stealthier
     See {stealthy}