Green’s Dictionary of Slang

(US) a derog. term for a Jew.

1893		F. Remington letter May in Splete Sel. Letters (1988) 171: Very interesting and dead right – make all the Moxies crazy and red in the face.
1931		D. Runyon in Collier’s 10 Jan. 10/3: I consider this [...] disrespectful, like calling Jewish people mockies, or Heebs, or geese.
1938		J. Weidman I Can Get It For You Wholesale 75: These mockies didn’t have to know how much we were making.
1943		I. Wolfert Tucker’s People (1944) 364: Love thy neighbour if he’s not [...] a squarehead or a mockie or a slicked-up greaseball from the Argentine.
1948		(con. 1944) N. Mailer Naked and Dead 93: ‘You’re a mockey,’ Whitey had told him.
1949		N. Algren Man with the Golden Arm 230: That mocky ain’t workin’ no door where I’m dealin’.
1952		(con. 1910s) ‘Harry Grey’ Hoods (1953) 15: Twenty-three skidoo, sheeny. Out of the park, you goddam mocky.
1955		E. Hunter Blackboard Jungle 235: It’s not okay, and you’ll snap right back and call Levy a kike or a mockie.
1967		L. Bruce Essential Lenny Bruce 39: I don’t wanna be there with those Mockies!
1971		J.D. Horan Blue Messiah 120: Just a little wise guy mocky.
1986		S. King It (1987) 53: Feeling more Jewish than they ever felt in their lives [...] feeling like mockies, sheenies, kikes.
1987		R. Campbell Alice in La-La Land (1999) 57: Wales had been known as Mocky Hush in her hooking days.