[1] : The Collaborative International Dictionary of English v.0.48

mischievous \mis"chievous\ mi^s"ch-evu^s, a.
   causing mischief; harmful; hurtful; -- now often applied
   where the evil is done carelessly or in sport; as, a
   mischievous child. "most mischievous foul sin." --shak.
   1913 webster

         this false, wily, doubling disposition is intolerably
         mischievous to society.                  --south.
   1913 webster

   syn: harmful; hurtful; detrimental; noxious; pernicious;
        destructive.
        1913 webster -- mis"chievously, adv. --
        mis"chievousness, n.
        1913 webster
see also:
mis"chievously mis"chievousness 

[2] : WordNet (r) 2.0

mischievousness
     n 1: an attribute of mischievous children syn: naughtiness, badness
     2: the trait of behaving like an imp syn: impishness, puckishness,
         whimsicality
     3: reckless or malicious behavior that causes discomfort or
        annoyance in others syn: mischief, mischief-making, deviltry,
         devilry, devilment, rascality, roguery, roguishness,
         shenanigan
see also:
naughtiness badness impishness puckishness whimsicality mischief 
mischief-making deviltry devilry devilment rascality 
roguery roguishness shenanigan 

[3] : Moby Thesaurus II by Grady Ward, 1.0

29 moby thesaurus words for "mischievousness":
   annoying, belie, color, devilment, devilry, deviltry, diablerie,
   distort, evil, falsify, garble, harm, hurt, impishness, injury,
   mischief, miscolor, misstate, odiousness, offensiveness, pervert,
   roguery, roguishness, sportiveness, teasing, twist, waggery,
   waggishness, warp

Mischievousness >> M Words
Mischievousness, definition of term: Mischievousness
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