Momus

Momus, in Greek fable, was the god of mockery and censure, and delighted in finding fault with gods and men.

When Neptune, Minerva, and Vulcan strove to prove which was the most skilful artist, Momus was chosen as judge to decide among them.

Neptune made a bull; Minerva, a house; and Vulcan, a man.

Momus declared that Neptune should have put the horns of the bull nearer the front, that he might fight better; Minerva should have made her house movable, so that she could remove it in case she had troublesome neighbors; Vulcan should have made a window in the man's breast, so that his thoughts could be seen.

All were so disgusted with his criticism, that they turned him out of heaven; and he died of grief because he could find no imperfection in Venus.

A chronic grumbler is therefore called "a Momus."