Green’s Dictionary of Slang

1. money in the form of coins, as opposed to notes.

1788		S. Low Politician Out-witted IV i: Money trash! Ready Rhino trash! Golden [...] money! I’m sure he couldn’t mean the hard stuff.
1856		Bell’s Life in Sydney 26 July 3/3: He was willing to exchange some of his ‘hard stuff’ for the equine flesh and blood in question.
1859		Matsell Vocabulum 40: hard Metal.
1872		Schele De Vere Americanisms 296: Money itself has in the United States, as in England, probably more designations than any other object – liquor alone excepted [...] hardstuff, or hard.
1924		G. Henderson Keys to Crookdom 407: Hard stuff. Coin.
1936		Mencken Amer. Lang. (4th edn) 577: Making an attribute do duty for the whole produces [...] apple-knocker for farmer, law for policeman, yip for dog, hard stuff for metal money, eye for Pinkerton detective, and big-house for prison.
1950		Goldin et al. DAUL 91/2: Hard stuff. Coins; change as distinguished from bills.

2. spirits, as opposed to beer.

1848		Bell’s Life in Sydney 13 May 2/3: -The Drunkards' Sheet at the Police-office on Monday numbered forty male and female sacrificants to hard stuff, stringy bark, and gin and bitterness.
1870		Mercury (Hobart) 23 Apr. 2/5: [from the Stranraer Free Press] [...] the hard stuff.
1874		Manchester Eve. News 9 June 4/5: Having [...] partaken pretty freely of the ‘hard stuff,’ they [...] proceeded homeward.
1876		St Louis Globe-Democrat 19 Jan. n.p.: He is generally expected to answer that he will take some ‘hard-stuff,’ which means plain whisky.
1880		Queanbeyan Age 25 Feb. 2/4: Colonial wine is not likely to take the sight from us. I wish we had some of the hard stuff.
1888		‘Rolf Boldrewood’ Robbery Under Arms (1922) 34: I can stand what any other man can, and without the hard stuff, either.
1899		Eve. Teleg. (Dundee) 15 Sept. 5/5: Although he had practically stopped the ‘hard stuff,’ he still continued to drink as much twopenny as he could get.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 82: HARD STUFF: spirits, as opposed to lemonade, lime juice, and waters and cordials of the temperance kind, which are called soft stuff.
1908		J. Guinan Soggarth Aroon 67: She asked me if ‘I’d be pleased to taste a little drop of sperits,’ [...] producing at the same time a black bottle of the ‘hard stuff’.
1921		Eve. Teleg. (Dundee) 10 Oct. 6/1: The companion asked for a gill of the ‘hard stuff,’ which was supplied. The premises were then raided, amnd a large quantity of whisky was found.
1931		(con. 1915) C.W. Willemse Behind The Green Lights 196: We have a glass of beer with our meals [...] there’s no need for hard stuff.
1940		F. Sargeson ‘Whie Man’s Burden’ in A Man And His Wife (1944) 15: They all started on the hard stuff and went on to beer later.
1950		‘Hal Ellson’ Tomboy (1952) 127: We’re going to drink hard stuff [...] Are you going to join us?
1965		B. Behan Confessions 250: It was a good hooley too, with plenty of the hard stuff and a bite to eat.
1978		F. Norman Dead Butler Caper 116: Chucking the hard stuff on top of the funeral sherry was asking for trouble.
1981		J. Ellroy Brown’s Requiem 102: I came by your place a few nights ago and you were passed out on the hard stuff.
1983		J. Byrell (con. 1959) Up the Cross 128: A few dozen tinnies [...] and the odd bottle of the hard stuff.
1995		I. Rankin Let It Bleed 77: You didn’t have to be too old to qualify for a nip of the harder stuff.
2005		J. Stahl I, Fatty 94: It was the pressure that made me guzzle the hard stuff.

3. (drugs, also harder stuff, hard gear, hard shit) drugs like narcotics, rather than tranquillizers, cannabis etc.

1952		Lait & Mortimer USA Confidential 124: Many students at this institution of higher learning have graduated from muggles to hard stuff.
1963		J. Rechy City of Night 97: Destinee’s last husband just got busted pushing hard stuff.
1972		C. Bukowski Erections, Ejaculations etc. 468: The users of harder stuff, the spoon and needle set.
1977		Rolling Stone 22 Sept. 42: He was also on some of the harder stuff.
1982		H. Beaton Outside In I ii: Nearly killed her when I told her, she led me to the hard stuff.
1993		E. Richards Cocaine True 34: Ain’t I tell you to go on no hard shit. [...] The other sons smoke reefer, but don’t do the hard stuff.
1997		(con. 1960s) A. Frewin London Blues 84: Sonny deals in most things including some hard stuff which is mainly used by white society people.
2000		N. Griffiths Grits 154: Am partial to-a blow meself, boy. No arm in it, it’s not proper drugs like, not ee ard stuff.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 84/2: hard gear(also hard stuff) n. heroin.
2005		P. Temple Broken Shore (2007) [ebook] We’re talking about sellin hard stuff to kids here.
2015		J. Stahl OG Dad 54: You can be off the hard stuff for decades, and, at mention of a freebie, your brain just kicks right back to junky-think.