(a.) Causing mischief; harmful; hurtful\; -- now often applied where the evil is done carelessly or in sport; as, a mischievous child.

annoying arch artful bad baleful baneful bothering bothersome corroding corrosive corrupting corruptive counterproductive damaging dangerous deadly deleterious destructive detrimental devilish disadvantageous disserviceable distressing elfish elvish evil foolish foxy frolicsome full of mischief harmful hazardous high-spirited hurtful ill ill-behaved impish injurious insidious irking irksome knavish larkish lethal malefic malevolent malicious malign malignant misbehaving mischief-loving naughty noisome noxious ominous paw perilous pernicious playful poisonous prankish pranksome pranky precarious prejudicial puckish rascally risky roguish scampish scapegrace scatheful sly spiteful sportive toxic trickish tricksy tricky venenate veneniferous venenous venomous vexatious vexing vicious virulent waggish wicked