Green’s Dictionary of Slang

1. (US) a fool; thus ham-headed, stupid.

1927		(con. 1914–18) L. Nason Three Lights from a Match 135: ‘Hey, ham-head,’ cried Rouge.
1955		E. Hoagland Cat Man 177: ‘That hamhead that wants a job. Damn circus is going to pot’.
1966		‘Tom Pendleton’ Iron Orchard (1967) 37: You go tell that big hame-headed [sic] sonofabitch that you assigned me to bunk three.
2005		D. Jenkins Slim & None 206: ‘[T]hat’s when Democrats were statesmen instead of hamheaded socialists and saboteurs’.

2. (US Und./prison) a police officer.

1954

J. Blake letter 12 Jan. in Joint (1972) 38: New Year’s Day two hamheads picked me up, took me in.