A jum.
My neighbor's child's mischievous smile makes me nervous.
A mischievous child is called unruly. It begins with the letter u.
imp
Rascal.
imp
a small, ragged, mischievous child
jackanapes
imp
It has come to my attention that this is "Pennsylvania Dutch" for "mischievous child".
We had to laugh at the little rascal, a real mischievous child
tyke
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