Green’s Dictionary of Slang

1. positive.

1710		R. Steele Tatler No. 230 n.p.: I believe I can’t do’t, that’s Pozz —.
1716		J. Addison Drummer III i: I will be flattered, that’s pos!
1738		Swift Polite Conversation 42: lady sm.: Do you say it upon Rep? nev.: Pozz; I saw her with my own Eyes; she sat among the Mobb in the Gallery, her own ugly Fizz. And she saw me look at her.
1791		‘Song’ in New Vocal Enchantress 33: Hum’d, and them humbugg’d, twaddy, tippy, poz / All have had their day, but now must yield to quoz.
1806		T.S. Surr Winter in London III 171: Not I, poz, – not I.
1825		S. Woodworth Forest Rose I i: But, seriously, I intend to see the city, that is poz.
1831		Navy at Home II 236: I’ll give Sly an order on my banker for ten pounds — pos!
1838		‘Alfred Crowquill’ Seymour’s Humourous Sketches (1866) 4: Shooting a pig ain't no lark — that 's poz.
1842		S. Lover Handy Andy 13: If Sack wins, Neck-or-nothing gets a pension, – that’s poz.
1842		Cornwall Chron. (Launceston, Tas.) 29 Oct. 2/6: The evangelical We, of the Aching-head Gazette, is no Teatotaller, that's pos.
1848		Boston Blade 8 July n.p.: He gets no more of our custom — that’s poz.
1855		Hereford Jrnl 10 Oct. 3/6: These gentle testimonials [...] which mary fortunately tied up in packets —some think in her garters — as ‘proof pos’ that she had been bidden for.
1865		‘Oh! What A Flare-Up’ Rambler’s Flash Songster 34: ’Twould have made your heart’s bleed to have seen him it’s pos.
1887		‘’Arry on the Jubilee’ in Punch 25 June 305/1: Well, she won’t be ashamed of ’er subjeck, that’s poz, dear old pal, and no flies!
1895		Truth (Sydney) 20 Jan. 2/4: This is ‘Nana’s’ last week. Pos.
1908		‘Doss Chiderdoss’ ‘The Lure of the Lucre’ Sporting Times 1 Aug. 1/4: She never looked at any other bloke but me, I’m pos, / Even if ’e was in uniform, a ‘swaddy’ or a ‘roz’.

2. inflexible [i.e. positive in a dogmatic way].

1890

‘’Arry on Equality’ in Punch 22 Feb. 85/1: Old Huxley’s wuth ten on him, Charlie, though he’s rather huppish and poz.