the head ; a kind of opprobrious word, used by way of contempt, probably alluding to a costard apple.
·noun The head; — used contemptuously. II. Costard ·noun An apple, large and round like the head. ...
Webster's Dictionary of the English Language
The head. I'll smite your costard; I'll give you a knock on the head. ...
Dictionary of The Vulgar Tongue by Francis Grose
A dealer in fruit, particularly apples. ...