Green’s Dictionary of Slang

tangle-leg n.

whisky; note also cits. 1861, 1865.

1858		G.W. Harris ‘Sut Lovingood’s Adventures in New York’ N.Y. Atlas XXI Aug. in Inge (1967) 139: They didn’t seem a bit more fear’d tu du hit than I’d be tu take a horn ove tanglelaigs whisky.
1861		in R.F. Burton City of the Saints 30: [note] ‘The new liquor called “Tangle-leg” is said to be made of diluted alcohol, nitric acid, pepper, and tobacco, and will upset a man at a distance of 400 yards from the demijohn.’.
1865		G.A. Sala My Diary in America I 120: Decoctions of quassia and gentian are mingled with a fiery kind of rum, called, from the labyrinthine gait to which its consumption leads, ‘tangle-leg.’.
1867		G.W. Harris Sut Lovingood’s Yarns 129: He’s layin off the wum ove a fence, onder a deck-load ove tangle-laig whisky.
1876		‘Dan de Quille’ Big Bonanza (1947) 285: But let me come home full of tangle-leg, sheep-herder’s delight, and tarant’ler juice, and that is the durndest shamedest dog above ground.
1882		W.A. Baillie-Grohman Camps in the Rockies 6: I knew too much of Western ‘tangle-leg’ and its vile poisonous qualities.
1909		J. Ware Passing Eng. of the Victorian Era.

In derivatives

tangle-legged (adj.)

drunk.

1851		Kalida Venture (OH) 11 Apr. 2/4: Drunk [...] tangle-legged.
a.1856		Burlington Sentinel in Hall (1856) 461: We give a list of a few of the various words and phrases which have been in use, at one time or another, to signify some stage of inebriation: [...] tangle-legged.
1885		Bulletin (Sydney) 5 Sept. 24/2: I knew I should never see her again, and so filled her husband up with what would give him ‘Dutch courage,’ when she should again open the door to him. He was quite tangle-legged when I left him, and must have had a fine time with the vixen.