knavish (adj.)
- abominable
- arch
- arrant
- atrocious
- bad
- base
- black
- blackguardly
- blamable
- blameworthy
- criminal
- damnable
- dark
- deceitful
- degraded
- devilish
- disgraceful
- elfish
- elvish
- evil
- execrable
- flagitious
- flagrant
- foolish
- foul
- heinous
- high-spirited
- impish
- improper
- infamous
- iniquitous
- low
- lying
- mendacious
- mischievous
- monstrous
- naughty
- nefarious
- notorious
- peccant
- playful
- prankish
- puckish
- rank
- rascally
- recreant
- reprehensible
- reprobate
- roguish
- scandalous
- scoundrelly
- shameful
- shifty
- sinful
- sportive
- tricksy
- unforgivable
- unpardonable
- unspeakable
- untruthful
- unworthy
- vicious
- vile
- villainous
- waggish
- wicked
- wrong
