DUCK (4)

Duck (dŭk), v. i. 1. 1. To go under the surface of water and immediately reappear; to dive; to plunge the head in water or other liquid; to dip.
In Tiber ducking thrice by break of day. Dryden. 2. 2. To drop the head or person suddenly; to bow.
The learned pate Ducks to the golden fool. Shak.