wigeon or widgeon (WIJ-uhn) - n., any of three common freshwater dabbling ducks of the genus Mareca (formerly Anas); a fool.
The three being the Eurasian wigeon (M. penelope), the American wigeon (M. americana) and the Chiloé wigeon (M. sibilatrix) of South America -- but usually the first is what's meant. All three are related to mallards and have a similar shape, though with different coloring in the male:
Thanks,
WikiMedia!
The name dates to around the start of the 16th century, but where it came from and how it came to be a now rare if not obsolete term of abuse is unknown.
---L.