Green’s Dictionary of Slang

cabbage-head n.

[SE cabbage + -head sfx; the shape and the supposed ‘vegetable’ matter of which the person’s brain is composed]

1. a fool, a stupid person.

[UK]Behn False Count IV ii: I defie thee, thou foul filthy Cabbage head, for I am mad, and will be valiant.
[Ire]J. O’Keeffe Wicklow Mountains 44: I’m neither a potatoe nor a turnip, old cabbage head.
[US]J.R. Lowell Biglow Papers 2nd Ser. 228: For take my word for’t, when all’s come an’ past, / The cabbage-heads’ll cair the day at last; / Th’ aint been a meetin’ since the world begun, / But they made (raw or bil’d ones) ten to one.
[US]Leavenworth Wkly Times (KS) 13 June 1/3: We cannot take lunk-heads, chowder-heads and cabbage-heads as figure heads this campaign.
[UK]G. Horncastle ‘Right Before the Missis Too’ [lyrics] I’ve had a dreadful row / All through a chum named Tommy Sheen, / I ought to call him cabbage-head, / He is so very green.
[US]Witchita Dly Eagle (KS) 6 Mar. 4/2: When the final bill is passed, / And parting words are said, / Each ‘Hayseed’ and each ‘Cocklebur’ / Appears a ‘Cabbagehead’.
[US]Salt Lake Herald (UT) 6 Oct. 2/5: What! [...] that girl called me a cabbagehead!
[US]A. Irvine My Lady of the Chimney Corner 78: Yer blinked, ye cabbage head.
[US]Clayton News (NM) 3 Feb. 2/4: At a flash of the brain it must shoot a wireless message into cabbagehead or king.
[US]S. Ornitz Haunch Paunch and Jowl 241: My chin seems to start at my cheek-bones. Hogshead belly and cabbage head.
[US]Mad mag. Jan. 19: Any cabbage-head knows that!
[US]R. Abrahams Deep Down In The Jungle 45: What do you mean jelly bean? / What I said, cabbage head.

2. (US drugs) someone who will try any drug.

[US]ONDCP Street Terms 5: Cabbage head — An individual who will use or experiment with any kind of drug.