Synonyms for Mischievousness (same or very similar meaning)
WordNet sense 1 (an attribute of mischievous children):
badness, naughtiness
WordNet sense 2 (the trait of behaving like an imp):
impishness, puckishness, whimsicality
WordNet sense 3 (reckless or malicious behavior that causes discomfort or annoyance in others):
devilment, Devilry, deviltry, mischief, roguery, roguishness, shenanigan, mischief-making, rascality
From the ODE community, based on WordNet
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