Green’s Dictionary of Slang

hollowhead n.

(US) an idiot.

[1851		Lancaster Gaz. 31 May 8/5: The Committee [...] qwere denied the use of the Athenaeum by its liberal and enlightened proprietor [...] for Mr Hollowhead’s — beg pardon — we mean Mr Hollywoake’s lecture].
1929		E. Dahlberg Bottom Dogs 64: If ther’s goin’ to be any work-out, I’ll take ker of it, get me, hollerhead.
1931		Burnett & Foley Story 16: ‘But are there any donkeys in America?’ a man put in. ‘Don’t be a hollowhead.’.
1936		Monks & Finklehoffe Brother Rat II ii: You hollow brain!
1957		Anders Price of Courage 20: Ol’ Hollow Head just about got us all kilt [HDAS].
1981		Eble Campus Sl. Fall 4: hollowhead – person with little common sense.
1984		Algeo Stud Buds and Dorks 7: An absent-minded or inattentive person...hollowhead [HDAS].
2003		S. De France Killer 86: [...] hollowhead, hammerhead, emptyhead & 40 year old MAMA’S BOY who needs signs to tie shoes, or wipe ass.

In derivatives

hollowheaded (adj.)

stupid.

1863		Virginia Eve. Bulletin in Nevada: A Guide (1940) 81: That beef-eating, blear-eyed, hollow-headed, slab- sided ignoramus, that pilfering reporter, Mark Twain.
1887		Retrospections of America 21: Even this man (far above the rank of the mass of bookmakers), would be unusually hollowheaded did he expect to find in a young and vigorous republic one of the results of a decrepit despotism.
1893		Report of the Iowa State Horticultural Society 143: Our pulpits are desecrated by hollowheaded orators.
1906		Brownsville Daily Herald (TX) 7 Apr. 3/2: Time spent on fashion fits you only for giddy, hollowheaded company.
1913		Mountain Advocate (Barbourville, KY) 26 Sept. 6/3: We heard a little hollow-headed, pie-faced fellow say [etc.].
1935		G.J. Nathan Passing Judgments 167: Youthful criticism that seeks to hide its own complete hollow-headed-ness in an indignant invocation of mental gifts in others.
1947		Reader’s Digest 50 136: He’s an ex-test pilot who's got a job way over his head and thinks if he makes enough records with other people's lives no one will find out what a hollow-headed humbug he is.
1971		R.D. Pharr S.R.O. 175: She was lucky as hell to find six hollow-headed husbands.
1990		Q. Wilder High Heaven 13: This was no hollow-headed blonde interested in only her fingernails, her hair and her plans for Friday night.