This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Having the characteristics of a knave; mischievous, roguish, waggish, rascally or impertinent

adj. Like or characteristic of a knave{3}; given to knavery; trickish; fraudulent; dishonest; villainous.

adj. Mischievous; roguish; waggish; rascally.

Like a knave; suited to a knave; tricky; dishonest; fraudulent: as, a knavish fellow; a knavish trick.

Roguish; waggish; mischievous.

Synonyms Trickish, rascally, unprincipled.

adj. marked by skill in deception

"And he took the hollow lyre and laid it in his sacred cradle, and sprang from the sweet-smelling hall to a watch-place, pondering sheer trickery in his heart — deeds such as knavish folk pursue in the dark night-time; for he longed to taste flesh."

artful   

trickish    fraudulent    dishonest    villainous    mischievous    roguish    waggish    rascally   

underhanded    thoroughpaced    popish    wily    unscrupulous    impish    gamesome    avaricious    dishonorable    dishonest