Green’s Dictionary of Slang

1. (also gazeka, gazoopus) a lout, a boor, a fool, also used joc./affectionately.

1909		Wodehouse Mike [ebook]‘Why is he called Gazeka?’ [...] ‘Don’t you think he looks like one?’.
1924		Our Navy 15 Dec. 30: What are you two gazookuses doing here? [HDAS].
1932		in B. Sagendorf Popeye 128: I’m one tough Gazookus/Which hates all Palookas [HDAS].
1933		Nicholson & Robinson Sailor Beware! I ii: The boys want you to ditch gazoopus, here, and come on over.

2. (also gazukus) a thing; thus the real gazookus, the genuine article.

1924		H.L. Wilson Professor How Could You! 109: Do it with real acting so the hicks (suburbanites) will think they’re getting the real gazukus. [Ibid.] 124: I will say you are the goods (the gazukus).
1952		J. Elfenbein Businesspaper Publishing Practice 139: Our product has a manganese steel gazookus which practically never wears out.
1964		M.S. Mayer What Can a Man Do? 10: It’s a great life only if you weaken, and this is the Hot Gospel, the Law and the Prophets, the Medes and the Persians, and the Real Gazookus.