Answer:
Thoreau is saying that it makes no sense for a simple man, who had nothing to do with the formation of such a beautiful pond, to name the pond. Giving the pond such a simple name as "Flint's Pond" is discrediting all of the beautiful animals and beings who dwell there such as the ducks, the fish, and the beautiful flowers. The pond was named in the selfish thought of money, rather than majesty.
A hyperbole is an extreme literary exaggeration. Such as, "I'm so hungry, I could eat a horse!" Obviously one person could not eat a horse, but instead uses a hyperbole to express his/her hunger.
