Green’s Dictionary of Slang

1. (US) a doctor, esp. in drug use; thus croaker joint, a hospital or a surgery; nut croaker, a psychiatrist.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1876		Cheshire Obs. 18 Nov. 7/5: He had been trying to ‘best the croaker,’ but the ‘croaker,’ as the doctor is styled, had got the ‘best’ so far.
1884		‘Career of a Scapegrace’ in Leicester Chron. 10 May 12/1: There’s a stepper [i.e. treadmill] at Carnarvon [...] I must get over the croker somehow.
1885		M. Davitt Leaves from a Prison Diary I 143: Devices resorted to by convicts [...] for the purpose of ‘taking in the croaker,’ have begot detection dodges on the doctors’ part also.
1894		‘Price Warung’ Tales of the Early Days 149: ‘Hansen oughter see th’ croaker,’ said Freeman.
1900		J. Conrad Lord Jim 151: I can assure you no man could have appeared less ‘in the similitude of a corpse,’ as that half-caste croaker had put it.
1906		‘O. Henry’ ‘The Love-Philtre of Ikey Schoenstein’ Four Million (1915) 123: Tim Lacy told me he got some once from a croaker uptown.
1914		Wash. Post 11 Nov. Miscellany 3/6: The peter man [...] calls the good doctor ‘croaker.’.
1925		J. Tully Beggars of Life 22: A guy’s dyin’ up here. Tell her to send for a croaker.
1931		Irwin Amer. Tramp and Und. Sl. 57: Croaker Joint. – A physician’s office; especially that in a prison.
1931		D. Runyon ‘Breach of Promise’ in Runyon on Broadway (1954) 22: She [...] goes to Tarrytown to get a croaker to see if my wounds are fatal.
1935		Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks n.p.: Croaker; Doctor.
1937		E. Raymond Marsh 373: On the croaker’s, or doctor’s, orders, they took him from A Hall to the hospital wing.
1940		W.R. Burnett High Sierra in Four Novels (1984) 332: Legally, I can’t practice: that’s why I’ve got these croakers.
1946		Mezzrow & Wolfe Really the Blues 95: The most he needed was some bicarbonate of soda and a physic, not a croaker.
1949		Monteleone Criminal Sl. (rev. edn) 62: croaker joint A hospital; a doctor’s office.
1952		W. Burroughs letter April in Harris (1993) 115: I thought the nut croakers had fucked him up permanent.
1953		‘William Lee’ Junkie (1966) 22: The old croaker on 102nd finally lost his mind and no drugstore would fill his scripts.
1959		Murtagh & Harris Who Live In Shadow (1960) 54: None of them croakers scuffling around was able to put tea down along with the wicked stuff would give you a habit.
1962		Ragen & Finston World’s Toughest Prison 796: croaker – A physician. [...] croaker joint – A physician’s office.
1968–70		Current Sl. III–IV (Cumulation Issue) 33: Croaker, n. A doctor who will write prescriptions for a drug user.
1972		E. Grogan Ringolevio 54: A long list of croakers who wrote scripts for ten, twenty, fifty dollars.
1981		J. Wambaugh Glitter Dome (1982) 21: More likely, treatment from some unlicensed Chinese croaker.
1990		J. Wambaugh Golden Orange (1991) 99: Making annual visits to a plastic surgeon where the croaker’s floor is slushy with sucked-out pheasant.
1995		J. Stahl Permanent Midnight 219: A Reseda croaker who peddled [...] any pill you wanted.
2006		F.X. Toole Pound for Pound 127: Go see your croaker to write you a scrip.

2. (US prison) the prison doctor.

1924		Morell Twenty-Fifth Man in Hamilton Men of the Und. 255: The prison ‘croaker’ was called to the dungeon.
1936		D. Maurer ‘Argot of the Und. Narcotic Addict’ Pt 1 in AS XI:2 120/2: croaker. An addict’s term, common also among other underworld folk, for a physician. In underworld argot, specialized to mean a prison doctor.
1970		‘Red’ Rudensky Gonif 4: The Croaker, an alcoholic medical has-been, took only a glancing observation before condemning me to the tubercular ward.
1978		R. Caron Go-Boy! 55: There were about a dozen inmates [...] waiting to be called in to see The Croaker.
1989		J. Morton Lowspeak.
1992		Bentley & Corbett Prison Sl. 104: Croaker A prison doctor.
2000		Texas Lawyer [journal] Gloss. of Texas Prison Sl. 8 Feb. : Croaker – A prison medical officer.

3. (UK und.) a patent medicine seller at fairs, markets etc.

1935

Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks n.p.: Croaker: Person who sells patent medicines at markets and fairs.