Green’s Dictionary of Slang

(US) an illegal drinking establishment where drink is sold in nips or small (orig. half-pint) measures.

1935		Bluefield Dly Teleg. (WV) 4 Jan. 6/2: It maybe that the liquor was bought in one of the 300 to 500 ‘speaks’ or ‘nip joints’.
1940		Times Dispatch (Richmond, VA) 4 Jan. 4/5: Operations of the ‘moonshiner’ has been curtailed [...] but the bopard is still fighting ‘nip joints’ and violations of regulations.
1950		Richmond Times-Dispatch (VA) 29 may 4/1: [headline] 35 Arrested In Liquor Raids [...] 20 Alleged ‘Nip Joints’ Found in East End.
1960		Pittsburgh Press (PA) sect. 2 9 Mar. 21/3: When sold in outlaw ‘nip joints’ it [i.e. moonshine whiskey] brings $1.50 a pint or about 30 cents for a half-tumbler ‘shot’.
1971		R.D. Pharr S.R.O. (1998) 17: What the hell was 5-C anyhow? Some kind of nip joint? But — hell! — the bars and liquor stores were still open.
1976		Dly Press (Newport News, VA) 19 Mar. 10/4: [headline] Police Cracking Down on ‘Nip Joint’ Problem. Vice Squad detectives [...] have raided four of the so-called ‘nip joints’.
1997		P. Cornwell Hornet’s Nest 42: He [...] was bleeding from the fight he had gotten into at the nip joint where he had been gambling and drinking Night Train Express fortified wine.
2000		B. Bilger Noodling for Flatheads (2001) 100: There have always been two sorts of moonshine: the decent stuff, which is kept at home and sold to neighbors, and ‘nigger likker,’ [...] shipped to anonymous [...] nip joints in the big city.

the Peacock Tavern in Gray’s Inn Lane, London, where Burton ale was sold in nips or half-pint measures.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Nyp Shop. The Peacock in Gray’s Inn Lane, where Burton ale is sold in Nyps.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) n.p.:
1811		Lex. Balatronicum.

to have a drink.

1861

Bell’s Life in Sydney 18 May 3/3: Bobby hastened to another grog shrine and ‘freshened’ the nip, with another bumper of Burton.