Gudgeon, guj'un, a small fish of the carp family. It is about eight inches long. It has a narrow, cylindrical body with a small barbel or feeler at each corner of the mouth. It is distributed throughout the fresh waters of Europe. Gudgeons keep close to the bottom of the streams or lakes. They are very easily taken with the hook and with any sort of bait. In popular usage, a gudgeon is a person easily deceived--one who swallows a bait readily.