Green’s Dictionary of Slang

1. (also yockele, yok, yokkeleh) a gentile.

1934		J. Franklyn This Gutter Life 197: They regard me just as what they call ‘a decent yock.’.
1961		(con. c.1935) R. Poole London E1 (2012) 22: Jeering shouts of ‘Ikey Moses’ and ‘Big-’ead’ [...] ‘Yokkelehs,’ [the Jewish boys] shouted, ‘yokkeleh schmerels!’.
1977		D. Powis Signs of Crime 207: Yockele East End Yiddish for Christian (commoner than ‘goy’), often used in a slightly derogatory sense.
1980		(con. 1920s–30s) Barltrop & Wolveridge Muvver Tongue 35: The Jewish children’s word for a gentile is ‘yock’. It means a fool.
1981		(con. c.1906) A. Harding in Samuel East End Und. 76: There were five Jewish boys in the gang – I was the only ‘Yok.’.
2024		J. Meades Empty Wigs (t/s) 957: Despite the size abuse from mooning yoks louting about on the beach [etc].

2. a fool.

1934		P. Allingham Cheapjack 189: Quite a number of words are Yiddish. These include [...] ‘snodders,’ for people who don’t spend; and ‘yocks,’ for chumps.
1971		T. Thackrey Thief 431: Big yock!
1980		(con. 1920s–30s) Barltrop & Wolveridge Muvver Tongue 35: The Jewish children’s word for a gentile is ‘yock’. It means a fool.