Adjectives

(s)devilish, rascally, roguishplayful in an appealingly bold way“a roguish grin”
(s)rascally, roguish, scoundrelly, blackguardlylacking principles or scruples“the rascally rabble”, “the tyranny of a scoundrelly aristocracy” (W.M. Thackaray), “the captain was set adrift by his roguish crew”