In the ancient Enireth script, "puddy" is a glyph of a giant pseudo-primate, and one connotation is "nobility". The "sphat" glyph is a sleek fish, commonly synonymous with grace. A "bilger" is a pack animal, and one of the symbols of Enireth politics, denoting the diligence of the working class.
Naturally, the antics of the "noble, graceful worker" fraternity quickly led people to use alternate meanings for the symbols. It took very little stretching for them to come up with "big, drunken asses."