Green’s Dictionary of Slang

bonehead n.1

[SE bone + -head sfx (1); the image is of the hardness of bone; Moore, Lexicon of Cadet Language (1993), suggests an alternative link to bone n.1 (1a) on pattern of dickhead n.]

1. (orig. US) a fool, a dullard, an idiot; thus as a term of address.

[US]Sun (NY) 18 Oct. 11/2: Only a bonehead ought to expect a mess o’ deep sea coal heavers to play ball.
[US]J. London Valley of the Moon (1914) 154: ‘You’re a bonehead,’ Bert sneered.
[US]G. Bronson-Howard God’s Man 28: That father of mine’s just the craziest old bonehead in the world.
[US]St Louis Post-Despatch 16 Jan. 25/2: I’ve got a new monnicker for you. I’m going to call you Bonehead Sweeney.
[US]C. McKay Banjo 221: You big bonehead.
[Aus]X. Herbert Capricornia (1939) 349: Heard you callin’ on the boneheads to rise and fight for their rights.
[US]Pittsburgh Courier (PA) 11 Mar. 11/1: Please [...] don’t let the prejudiced bone-heads get away with it.
[UK]G. Fairlie Capt. Bulldog Drummond 212: Surely this bonehead would understand that argument?
[US]P. Rabe Benny Muscles In (2004) 277: You can use both of them [i.e. fingers], bonehead.
[US](con. 1940s) G. Mandel Wax Boom 304: I’m nobody’s bonehead.
[UK]S. Berkoff East in Decadence and Other Plays (1985) 75: Of course I’m not ninety-six you stupid bonehead.
[UK]T. Paulin ‘Waftage: An Irregular Ode’ in Fivemiletown 7: Wiser – / aye, I used to think wiser – / than us boneheads here.
[UK]N. Barlay Curvy Lovebox 51: Look a’ them muggy boneheads.
[SA]IOL News (SA) 23 July [Internet] The term ‘bonehead’ did not refer to the race of the rugby hero but to his alleged stupidity.
[US]N.Y. Rev. of Books 27 Sept. 8/4: And there were the same boneheads among them.
[SA]Mail & Guardian (Johannesburg) 24 Feb. [Internet] Portraying [George W.] Bush as a bonehead. Piece of cake. No one is offended.
[UK]Guardian CiF 14 Dec. [Internet] Is a democracy sausage what comes back to FU when a majority of boneheads vote in a wingnut LNP.

2. in attrib. use of sense 1.

[US]Sun (NY) 22 Sept. 7/1: All on acct.of some bonehead Frensh solders [sic] who was wandering around.
[SA]Mail & Guardian (Johannesburg) 2 May [Internet] Let that bonehead white supremacist display his total idiocy to the world by waving the old South African flag.

3. a stubborn person.

[US]H.L. Wilson Professor How Could You! 141: Well, you old bonehead (one of strong character!).
[US]T.J. Farr ‘The Language of the Tennessee Mountain Regions’ in AS XIV:2 89: bonehead. Stubborn or unruly.
[US]Wentworth & Flexner DAS.
[WI]V. Bloom ‘Sun a-shine, rain a-fall’ in Duppy Jamboree 14: The devil call him wife bonehead, / She hiss her teeth, call him cock-eye.
[US]C. Hiaasen Nature Girl 286: Don’t die on me, you big bonehead.

4. a stupid error.

implied in pull a boner under boner n.3
[US]J. Thompson Swell-Looking Babe 53: That was her biggest bonehead, checking in [...] without a reservation.
[US]Wentworth & Flexner DAS.

5. (S.Afr.) an Afrikaaner; also as adj.

[SA]A. Lovejoy Acid Alex 17: The same kid taught me [...] all the words for Rockspiders – Crunchies, Hairybacks, Clutchplates, Planks, Ropes, Boneheads, Durchmen – . [Ibid.] 194: The stupid bonehead bullies have never come across a mallit who knows how to fight in handcuffs.

In compounds

bonehead English (n.)

(US campus) a remedial course in elementary English composition.

[US]W.R. Morse ‘Stanford Expressions’ in AS II:6 275: bonehead English — English for insufficiently prepared freshman.
[US]C. McFadden Serial 31: He [...] was currently teaching night classes in bonehead English.
bonehead play (n.) [play n. (2); note locus classicus the ‘bonehead play’ committed by Giants 19-year-old Fred Merkle rookie substitute in Giants vs. Cubs game on 23 Sept. 1908; the term was coined by the NY press which headlined ‘Merkle’s Bonehead Play’]

(US) an elementary, obvious error or mistake; thus pull a bonehead play, to make an elementary error.

[US]A.H. Lewis Apaches of N.Y. 10 7: I don’t know as I’d call it a vice so much as a bonehead play.
[US]Lincoln (NE) State Journal 3 June n.p.: Some famous bonehead plays have been pulled in this city, but no council ever equalled the record of the present commissioners.
[US](con. 1917–18) C. MacArthur War Bugs 105: Shelter halves were oozing with mud, another result of the bonehead play.
[US]E. O’Neill Long Day’s Journey into Night Act I: Harke came in person to rebuke Shaughnessy. (He chuckles.) A very bonehead play!
[US]Bowers Mob [film] It sounds like a bonehead play, but the badge he flashed was the McCoy [HDAS].
[US]C. Perry Portrait of a Young Man Drowning (1963) 121: That was a bonehead play.
[US]N.Y Post 23 Mar. 89: The individual made a bonehead play, in my judgment [HDAS]. 30 Sept. [Internet] Watching the games this past Saturday, even the most casual football fan had to be scratching their heads, and other parts of their bodies, watching some of the bonehead plays coaches called which were tantamount to handing your enemy a loaded gun.
[US]Dave Chun 7 Nov. [blog] Rich and I ended up leaving first and we forgot to pay our drink tabs before we left! Aiyee. What a total bonehead play. Now Jish et al. are sending Guido to break our legs.

In phrases