noun /ˈmɪstʃɨf,ˈmɪʃtʃɨf/
a) Harm or evil caused by an agent or brought about by a particular cause.
b) One who causes mischief. In a milder sense, one who causes petty annoyances. mischief-maker.
Syn: agitation, annoyance, corruption, damage, demolition, destruction, detriment, disablement, disruption, evil, harm, hurt, ill, impairment, incapacitation, injury, nuisance, pique, ravage, sabotage, scathe, trouble, undoing, unmaking, vexation, weakening, wrong, bad boy, booger, buffoon, bugger, cutup, devil, elf, enfant terrible, fun-maker, hell-raiser, hood, hoodlum, hooligan, imp, joker, jokester, knave, life of the party, little devil, little monkey, little rascal, minx, mischief-maker, pixie, practical joker, prankster, puck, rapscallion, rascal, rogue, rowdy, ruffian, scamp, scapegrace, thug, trouble maker, vandal, wag, bad manners, badness, delinquincy, devilishness, devilment, devilry, deviltry, disobedience, elfishness, goings-on, hanky-panky, impishness, impropriety, misbehavior, mischievousness, misconduct, misdemeanor, monkey business, naughtiness, prankishness, pranksomeness, puckishness, rascality, roguery, roguishness, scampishness
Wikipedia foundation.