The Collaborative International Dictionary of English v.0.48:

Scampish \Scamp"ish\, a.
   Of or like a scamp; knavish; as, scampish conduct.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "scampish":
   arch, base, blackguardly, degraded, devilish, elfish, elvish,
   foolish, full of mischief, high-spirited, impish, infamous,
   knavish, mischief-loving, mischievous, notorious, playful,
   prankish, pranksome, pranky, puckish, rascally, recreant,
   reprobate, roguish, scapegrace, scoundrelly, sportive, trickish,
   tricksy, vile, villainous, waggish