Green’s Dictionary of Slang

(US tramp) irrational fear of the police.

1917		Labor Jrnl (Everett, WA) 2 Mar. 1/5: The workers who were made to appear before this modern inquisition were [...] bullied into signing a statement [and] every effort was made to instil into their hapless prey the ‘bull horrors’.
1927		C. Samolar ‘Argot of the Vagabond’ in AS II:9 391: Horrors is a choice expression and travels atttached to four adjectives. It has the meaning of ‘phobia’. Bull horrors and work horrors are self-explanatory.
1930		J. Tully Shadows of Men 187: [chapter title] Bull Horrors.
1935		A.J. Pollock Und. Speaks 15/1: Bull horrors, from the effect of a large dose of opium, morphine, cocaine or heroin, person believes every stranger a police officer, and is disturbed by the slightest sound.
1936		(ref. to 1920s) L. Duncan Over the Wall 28: He had just been released a few days before from a penitentiary down in Oklahoma, still had the ‘bull horrors’ to a certain extent.
1949		N. Algren Man with the Golden Arm 256: You always get scared too soon. You got the bull horrors.
1962		Ragen & Finston World’s Toughest Prison 792: bull horrors – A morbid fear of the police.
1971		T. Thackrey Thief 289: I finally got the bull horrors, though, reading the newspapers about how there was a crime wave going on.
1980		(ref. to c.1930s) R.A. Bruns Knights of the Road 200: Bull horrors. Obsessive fear of police.
1995		Adman posting at www.catalogo.com 🌐 Remember, spending a night in jail is a relevant experience too. Shun the bull horrors, be careful, and don’t let the mad dog bite ya.