Green’s Dictionary of Slang

1. (orig. US) something very successful, a hit; also as adj.

1936		J.T. Farrell World I Never Made 191: They should forge ahead with the old sockerino.
1942		Time 9 Nov. 77/2: The act was an old-fashioned Hippodrome sockeroo.
1949		Dundee Eve. Teleg. 21 Sept. 2/3: Senator Margaret has been called ‘the biggest, bang-up sockeroo New England story’.
1951		J. Reach My Friend Irma II ii: An A-number-1, twenty-two carat, gold-lined sockeroo?
1953		Lancs. Eve. Post 17 Nov. 6/5: The men of feature film, whose language inclines rather to ‘oaties,’ ‘weepies,’ ‘sockeroo’ and ‘giving a nigger’.
1964		Spectator 7 Feb. 178: This latest box-office sockeroo also provides a modest example of the industry’s throat-cutting activities.
1977		Daily Tel. 22 Apr. 13: The Royal Court’s new régime opens with a great loud sockeroo of a play, a thumping American drama of a divided family, rich in purple prose and loaded with gutsy symbolism.
1997		W. Denton posting 21 Mar. to ‘Rara-Avis: What Are you Reading’ on Miskatonic.org 🌐 However, with this recommendation, I’ll try him or her out. Would this be a good one to start with, or is there one sockeroo book I should start with?
2001		G. Erickson ‘DVD Savant: Pearl Harbor Rev.’ on DVDTalk 🌐 It was definitely a success last summer, but not the runaway sockeroo to rival Titanic, the benchmark it obviously strived to pass.

2. (US) power, physical strength.

1940

Jefferson City Post-Trib. (MO) 26 Aug. 5/4: [He] has so much sockeroo in both hands [...] he will be a heavyweight champion .

3. a blow.

1959

A. Sinclair My Friend Judas (1963) 39: Then I landed him the old sockeroo slap bang in the gin-trap.