Green’s Dictionary of Slang

stupid, foolish.

1751		Smollett Peregrine Pickle (1964) 305: As for that thick-headed, insolent pedant, his confederate, who emptied my own jordan upon me while I slept.
1788		Morris et al. ‘Denis O’Neal’ Festival of Anacreon (1810) 76: But you won’t make a Judy of Denis O’Neal. / With your jumping, jungling, grinning, mouthing, / Clout-headed, thick-headed, brazon-nos’d, copper-fac’d, / Ill looking thief!
1800		T.G. Fessenden ‘Belgic War-Whoop’ Poems (1804) 12: Clump-headed Dutchman, why are you so stupid?
1812		J. Bell Jr. (ed.) Rhymes of Northern Bards 105: An’ smash me! I thought him a thick-headed fool.
1822		Life and Trial of James Mackcoull 292: The other driver [...] was a stupid thick-headed boy.
1838		Dickens Oliver Twist (1966) 270: I have told that thick-headed constable-fellow downstairs that he mustn’t be moved or spoken to.
1842		S. Lover Handy Andy 7: Go out of this, you thick-headed villain!
1850		Hereford Jrnl 30 Jan. 4/1: The thick-head offspring [...] That oftimes crushed modest merit.
1852		C.L. Canfield Diary of a Forty-Niner (1906) 178: Am I not better employed [...] beating law into the skull of a thick-headed judge, who don’t know Blackstone from white quartz?
1868		H.L. Williams Three Black Smiths in Darkey Drama 4 30: Thick-headed darkey! you don’t know more than is good for you.
1877		Worcs. Chron. 21 July 3/1: Unconscious fools! [...] Drift along ye thickhead throng.
1878		Scotsman 22 Sept. 6/3: Sir — I may be very thick-headed but your post-note [...] does not appear to me to deal with the whole of the point .
1888		R. Barnett Police Sergeant C 21 132: If you’re too thick-headed to see it, we’re not.
1890		Sporting Times 29 Mar. 1/1: Let a girl in Regent Street some night be ‘run in’ in an outrageous manner by some thick-headed policeman.
1897		M.H.E. Hayne Pioneers of the Klondyke 116: Why, you thick-headed chump!
1901		Boy’s Own Paper 15 June 577: The boys may be a bit thick-headed, but most of ’em are honest.
1909		N.Z. Truth 30 Jan. 5/6: A thick-headed bobby.
1910		Marvel 5 Feb. 9: Good-hearted, thick-headed Joe.
1916		Joyce Portrait of the Artist as a Young Man 79: Here, Maurice! Come here, you thickheaded ruffian! Do you know I’m going to send you to a college where they’ll teach you to spell c.a.t. cat.
1923		Hull Dkly Mail 5 Apr. 3/3: Now, Mr Mule was a very thick-headed fellow.
1935		L. Hughes Mulatto in Three Negro Plays (1969) Act I: Is that damn Frigidaire working right? Or is Livonia still too thick-headed to know how to run it?
1947		W.D. Overholser Buckaroo’s Code (1948) 125: Then he shook his head. ‘I guess I’m kind o’ thick-headed.’.
1956		J. Curtis Look Long Upon a Monkey 203: This cousin must be a thick-headed clot.
1967		N. Dunn Poor Cow 24: He understood about despair and clinging on and all sort of wild feelings that Tom had never understood, being just a thick-headed thug.
1978		J. Krantz Scruples 31: Blast that thickheaded Joe anyway.
1989		Kirk & Madsen After The Ball 308: Being a bit thickheaded, hovever, it took us some time to realize.
1999		Indep. Rev. 28 June 10: The thick-headed football captain.
2006		Tucson Citizen (AZ) 27 Sept. Taste Plus 21/3: The thick-headed (not necessarily unintelligent , just — thick) [...] may have the capacity to learn something.
2017		LNP Always (Lancaster, PA) 31 Aug. 23/4: ‘That’s thickheaded, but not as thickheaded as A&W. And sometimes it’s good to be thickheaded’.