Wordnik has a nice little post which covers some of the clever wordplay, especially in the names, of the Harry Potter books, for example:

A dumbledore is a bumblebee. Snape is a ship-building term that means “to bevel the end of (a timber or plank) so that it will fit accurately upon an inclined surface.” Hagrid is the past participle of hagride, which means “to harass or torment by dread or nightmares.” Skeeter is a term for an annoying pest, and not just Rita Skeeter, blood-sucking journalist. Mundungus is “waste animal product” or “poor-quality tobacco with a foul, rancid, or putrid smell,” a good name for a sneaky thief.

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