Green’s Dictionary of Slang

a fool, a simpleton.

1837		A. Greene Glance at N.Y. I v: Louder, old puddin’-head! louder!
1841		Punch 24 July I 22: They named me Puddinghead.
1851		Melville Moby Dick (1907) 408: Look ye, pudding-heads should never grant premises.
1852		Worcs Jrnl. 13 May 3/6: Defendant came, and after calling him ‘pudding head,’ punched his head.
1865		G.A. Sala A Trip to Barbary 136: Pudding-head may be either a Papist or a ‘Swaddler’.
1875		Ariz Sentinel (Arizona City) 15 Jan. 4/3: Old pudding-head seemed struck aghast.
1886		N.Z. Observer and Free Lance (Auckland) 20 Mar. 23/1: When that par appeared in the Observer about the U.C.C. ‘puddin’ heads’ they all stared at each other to see who it referred to.
1889		Dead Bird (Sydney) 28 Sept. 1/4: ‘You slick-fingered, smooth-jawed puddin’ head’.
1890		Bird o’ Freedom 22 Jan. 1: You slick-fingered, smooth-jawed puddin’ head!
1897		‘Mark Twain’ Tom Sawyer, Detective 29: He put up that scheme on us and [...] we went ahead and done it perfectly exact, like a couple of pudd’n-heads.
1904		Sydney Sportsman (Surry Hills, NSW) 30 Mar. 6/3: [A] few full-throated pudding-heads hootod Pat for hitting low.
1906		C.B. Loomis Cheer Up! 175: I’d give five dollars to be on hand when that old puddinghead tumbles to the fact that the old lady doesn’t belong to me.
1911		G. Stratton-Porter Harvester 518: ‘You puddin’ head! You blunderbuss!’ cried Granny.
1915		Eve. Public Ledger (Phila., PA) 13 Dec. 4/3: Are you a [...] swell-head, a puddin’-head or any other kind of head?
1934		Central Qld Herald (Rockhampton, Qld) 26 July 12/4: As may be guessed by his nick-name Pudd’nhead was the champion dull boy of the country school.
1940		E. Curry Hysterical Hist. of Aus. 175: And now, my pen-pushing puddenheads, we come to the final chapter.
1956		H. Ellison ‘Johnny Slice’s Stoolie’ in Deadly Streets (1983) 78: I’ll cut you open from your crotch ta your lousy pudding head.
1973		J.K. Baxter ‘Letter to Sam Hunt’ in Coll. Poems (1979) 430: Her husband, that sad pudding-head, / Will pull himself each night in bed.
1977		A. Bleasdale No More Sitting on the Old School Bench (1979) 65: lurch Puddin’ brain. [...] miss mckensie Scum.
1983		J. Ciardi A Second Browser’s Dict. 227: Puddin’ head. A dolt.
1994		P. Jonas To Spite the Devil 17: You’re a damned puddinghead.