Green’s Dictionary of Slang

1. the human head.

1512		Hickscorner Bi: I wyll rappe you on the costarde with my horne.
1533		J. Heywood Pardoner and Friar Biii: And yf thou playe me suche another touche / Ish knocke thee on the costarde.
1550		Udall Ralph Roister Doister III v: I knock your costard, if ye offer to strike me.
1566		G. Gascoigne (trans.) Supposes IV vii: I will rap the old cackabed on the costard!
1575		‘Mr. S’ Gammer Gurton’s Needle in Whitworth (1997) V ii: Well, knave, and I had thee alone, I would surely rap thy costard!
c.1580		‘I.T.’ Grim The Collier of Croydon IV i: I receiv’d it upon my bare Costard.
1592		Arden of Feversham in Sturgess (1969) 130: Now his way had been to have come hand and feet, one and two round at his costard.
1605		Shakespeare King Lear IV vi: Keep out [...] or ise try whether your costard, or my ballow be the harder.
1616		W. Haughton English-Men For My Money I 2: Old Fornicator, had I my Dagger, Ide breake his Costard.
c.1629		R. Brome City Wit V i: How does your Costard Sir?
1633		Jonson Tale of a Tub III iv: I had crack’d all their costards.
1657		Marlowe Lascivious Queen IV v: I’le knock any bodies costard.
1676		D’Urfey Madam Fickle I i: You shall drink Bumpers out of your Custard [sic] – Cap you Rogue.
c.1698		B.E. Dict. Canting Crew n.p.: Costard the Head. I’ll give ye a knock on the Costard, I’ll hit ye a blow on the Pate.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Costard, the head. I’ll smite your costard; I’ll give you a knock on the head.
1817		W. Scott Rob Roy (1883) 163: It’s hard I should get raps over the costard.
1822		R. Nares Gloss. (1888) I 193: costard. A man’s head; or a large apple. Which is the original sense is not yet settled.
1862		E. de la Bédollière Londres et les Anglais 313/2: costard, la tête. I’ll smite your couard, je vais vous fendre la tête.
1873		Sl. Dict. 129: Costard the head. A very old word, generally used in connexion with ‘cracked’.

2. a term of insult.

1850

E.V. Kenealy Goethe: a New Pantomime in Poetical Works 2 (1878) 336: Costard, Couple-beggar, Duffer, / You look handsome in your dumps.