E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Coot.
A silly old coot. Stupid as a coot. The coot is a small water-fowl.
1
Bald as a coot. The coot has a strong, straight, and somewhat conical bill, the base of which tends to push up the forehead, and there dilates, so as to form a remarkable naked patch.
