Source : Webster's Revised Unabridged Dictionary (1913)

Roguish \Rogu"ish\, a.
   1. Vagrant. [Obs.] --Spenser.

            His roguish madness Allows itself to anything.
                                                  --Shak.

   2. Resembling, or characteristic of, a rogue; knavish.

   3. Pleasantly mischievous; waggish; arch.

            The most bewitching leer with her eyes, the most
            roguish cast.                         --Dryden.
      -- {Rogu"ish*ly}, adv. -- {Rogu"ish*ness}, n.

Source : WordNet®

roguish
     adj 1: playful in an appealingly bold way; "a roguish grin" [syn: {devilish},
             {rascally}]
     2: lacking principles or scruples; "the rascally rabble"; "the
        tyranny of a scoundrelly aristocracy" - W.M. Thackaray;
        "the captain was set adrift by his roguish crew" [syn: {rascally},
         {scoundrelly}, {blackguardly}]