Green’s Dictionary of Slang

an all-purpose excl./interrog. in which the speaker, according to context, makes fun of the subject of the excl.

1789		Bury & Norwich Post 23 Sept. 4/2: Origin of the present fashionable word Quoz. [...] They saw[that] the passengers were none of the common sort of men, they asked very exorbitant prices for bringing them and their baggage on shore [...] upon which the Frenchmen [...] sent the general cry of ‘Qui, quoi, quoi, ’ (in English, ‘What, what, what.!) The pilots immediately cried out, ‘Damn your Quoz, quoz, quoz, speak that we may understand you and don’t bore us with your Parley vous and Quoz’.
1791		New Vocal Enchantress 91: Hey for buckish words, for phrases we’ve a passion / [...] / hum’d and then humbugg’d, twaddy, tippy, proz, / All have had their day, but now must yield to quoz.
1802		in Spirit of Public Journals VI. 197: At length it was announced, that Pic-Nic, like Quoz, which was chalked some years ago on windows and doors, really meant nothing .
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 144: Quoz — a quiz upon the public, when it was formerly chalked all about town.
1841		C. Mackay Memoirs of Extraordinary Popular Delusions (1869) 240: Many years ago the favourite phrase (for, though but a monosyllable, it was a phrase in itself) was Quoz. This odd word took the fancy of the multitude in an extraordinary degree, and very soon acquired an almost boundless meaning. When vulgar wit wished to mark its incredulity, and raise a laugh at the same time, there was no resource so sure as this popular piece of slang. When a man was asked a favour which he did not choose to grant, he marked his sense of the suitor’s unparalleled presumption by exclaiming Quoz! When a mischievous urchin wished to annoy a passenger, and create mirth for his comrades, he looked him in the face, and cried out Quoz! and the exclamation never failed in its object. When a disputant was desirous of throwing a doubt upon the veracity of his opponent, and getting summarily rid of an argument which he could not overturn, he uttered the word Quoz, with a contemptuous curl of his lip and an impatient shrug of his shoulders.
1839		Liverpool Mercury 6 Dec. 2/5: The consequence was that the first question put by the Cockneys on meeting was [...] ‘What in the world does Quoz mean?’.
1852		Stonehaven Jrnl 9 Nov. 4/2: Whjen a man was asked a favour which he did not chooe to grant, he marked [...] the presumption by exlaiming Quoz!
1927		(con. 1835–40) P. Herring Bold Bendigo 111: Oh, quoz! What a shocking bad hat.