Grumplin
A person who is small, mousy, impish, and greasy in demeanor. A grumplin is typically intensely repulsive for a non-apparent reason. Common actions of a grumplin include sniveling and cackling.
Sophie: Who's that little greasy girl sniveling in the corner? I couldn't explain it, but her impishness just repulses me!

John: I'm not sure...but she's quite a grumplin.