Synonyms for Mischief (same or very similar meaning)
WordNet sense 1 (the quality or nature of being harmful or evil):
balefulness, maleficenceWordNet sense 2 (reckless or malicious behavior that causes discomfort or annoyance in others):
devilment, Devilry, deviltry, mischievousness, roguery, roguishness, shenanigan, mischief-making, rascalityFrom the ODE community, based on WordNetadd/edit