Thesaurus

Synonyms for Mischievous include:

abominable, abusive, atrocious, awful, bad, bruising, calumniatory, calumnious, catastrophic, coltish, corked, corky, counterproductive, crappy, damaging, defamatory, deleterious, denigrating, denigrative, denigratory, deplorable, destructive, detrimental, devilish, disadvantageous, disobedient, distressing, dreadful, elfin, elfish, elvish, evil, fearful, frightful, frisky, frolicky, frolicsome, hard, harmful, hopeless, horrid, hurtful, icky, ill, impish, implike, incompetent, injurious, insidious, kittenish, lamentable, libellous, libelous, lousy, malign, mediocre, mischievous, mocking, naughty, negative, no-good, nocent, noxious, offensive, painful, pernicious, pitiful, pixilated, playful, poor, prankish, prejudicial, prejudicious, pretty, puckish, quizzical, rascally, roguish, rollicking, rotten, rubber, ruinous, sad, severe, slanderous, sorry, sportive, stabbing, stinking, stinky, subtle, swingeing, teasing, terrible, tough, toxic, uncool, unfavorable, unfavourable, unskilled, unspeakable, unsuitable, unwholesome, wicked, worse, worst, wounding

mischievous is a ADJ.