Green’s Dictionary of Slang

1. an appalling person, thing or situation.

1890		Sporting Times 8 Feb. 1/5: An earthquake is a shock; but the ghost of Hamlet’s father is a shocker.
1926		Western Times (Exeter) 12 Feb. 7/5: Not a very thrilling document, you might say, but I can tell you it is a shocker.
1933		Western Gaz. (Somerset) 17 Feb. 11/6: Shaw, The Shocker! What the ‘Great’ Man Told university Students.
1944		M. Panter-Downes ‘The Danger’ Wartime Stories (1999) 170: She’s a shocker. You’ll have to get rid of her, Mother.
1949		R. Park Poor Man’s Orange 210: She fished in her pocket for her rosary beads [...] hoping the dentist wasn’t the hairy old shocker he had been in her day.
1951		C. Duffy San Quentin 1: The film was advertised as a ‘shocker’.
1960		Galton & Simpson ‘The Reunion Party’ Hancock’s Half-Hour [TV script] Whatever became of that ATS girl you were knocking about with? [...] Oh she was a shocker.
1966		H.S. Thompson Hell’s Angels (1967) 154: The real shocker, however, was the beer situation.
1978		(con. 1940s) O. Manning Battle Lost and Won 264: To think she would take up with a shocker like Castlebar!
1985		S. Berkoff West in Decadence and Other Plays (1985) 97: That was a shocker.
1995		G. Small Ruthless 89: Manley’s first ‘shocker’ came in the first week of January 1977.
1999		Guardian G2 29 July 23: A promising thriller fades into a conventional, if well-executed, shocker.
2000		Indep. Rev. 28 Jan. 10: The unspeakable Japanese POW shocker Paradise Road.
2011		Eve. Standard 17 Feb. 51/4: It’s been a shocker of a year for the music business.

2. see shilling shocker under shilling n.