Green’s Dictionary of Slang

1. (US, also gazoo, gazoop) a lout, a boor, a fool.

1901		W. Irwin Love Sonnets of a Hoodlum III n.p.: Then I shall strive and be the great main squeeze, The warm gazook, the only on the bunch.
1912		Ade Knocking the Neighbors 177: Once [...] there lived a blue-eyed Gazook named Steve.
1914		E. Pugh Cockney At Home 119: He was once more the Great Gazoo of the Monkey Parade.
1917		Wkly Tribune & Cape Co. Herald (Cape Girardeau, MO) 24 Apr. 6/6: One of them gazooks come up to me and tried to spread some of that stuff.
1929		M. Levin Reporter 133: Reciting his experience to a bearded old gazook who was an eyewitness.
1936		J.T. Farrell World I Never Made 153: He ain’t married. That’s why he ain’t got gray in his head like this gazook.
1942		Berrey & Van den Bark Amer. Thes. Sl.
1969		in DARE.

2. (also gazooka) a person, a fellow.

1904		Ade ‘The Fable of the Two Ways of Going Out After the Pay Envelope’ in True Bills 99: When he was finally admitted to the Sacred Presence of the Head Gazooks, he would approach the Roll-Top on tiptoe.
1914		Ade ‘The New Fable of the Private Agitator’ in Ade’s Fables 12: If he wanted to reason out a Deal with a contrary-minded Gazook, he began the Negotiations by soaking the Adversary behind the Ear.
1938		R.L. Bellem ‘Grappling Trilby’ in Popular Sports June 🌐 ‘Svengali is the central character in the play “Trilby”,’ the tall gazooka elucidates.

3. (US tramp, also gazock) a tramp’s young (homosexual) companion.

1933		Ersine Und. and Prison Sl. 39: gazock, gazooney, n. A lad. ‘Send the gazooney after a couple of pints.’.
1949		Monteleone Criminal Sl. (rev. edn).
1972		R.A. Wilson Playboy’s Book of Forbidden Words.