Green’s Dictionary of Slang

(US) a fool, an idiot; thus ass-headiness, foolishness.

1546		Becon Early Writings n.p.: [A fool is called] asshead [F&H].
1550		Bale Apology 61: O absolute ass-heads [...] and wytlesse ydyote [F&H].
1589		Hay any Work 36: As verye an Assehead as John Catercap [F&H].
1600		Shakespeare Twelfth Night V i: An ass-head and a coxcomb and a knave.
1617		J. Minsheu Ductor in Linguas n.p.: Asshead, or blockhead. [Ibid.] Asse-headdinesse or blockishnesse.
1638		Rowley Shoo-maker, a Gentleman Act IV: I smell an Asse-head of your own.
1819		Morn. Chron. 9 Mar. 2/2: The one should call the other ‘an asshead’.
1828		London Standard 24 Mar. 3/2: Here is the Asshead gaping.
1846		Portage Sentinel (Ravenna, OH) 7 Jan. 1/2: Col. Gristle didn’t relish it much to hear his sider called a asshead.
1850		E.V. Kenealy Goethe: a New Pantomime in Poetical Works 2 (1878) 336: Ass-head, Blackmoor, Cuckoo, Dotard, / Splay foot, Yelper, wry-necked Wretch.
1942		L. Bennett ‘John Cunnoo’ Jam. Dialect Poems 22: Go dung King Street an meck we meet / Nuff ass-head an John cunnoo.
1965		A. Lurie Nowhere City 26: ‘You know what I want, ass-head,’ Glory said.
1967		N. Mailer Why Are We in Vietnam? (1970) 143: So, ass-head America, contemplate your butt.
1999		P. Temple Black Tide (2012) [ebook] Same problem them if there’s two of you or fifty-two testosterone-crazed arseheads with guns.
2000		P. Temple Dead Point (2008) [ebook] Like you get to the big-time by being such an arsehead that the delivery boys can take the Feds to you.
2002		posting at MrCranky.com 3 May [header] And Hate Guy is a complete asshead.
2003		Eble Campus Sl. Nov. 1: asshat – someone stupid, mean, or annoying.
2017		D. Winslow The Force [ebook] Asshats who think that the answer [to crime] is to arm every one.