Green’s Dictionary of Slang

1. (also snagg) a large tooth.

c.1698		B.E. Dict. Canting Crew n.p.: Snaggs large Teeth.
1718		M. Prior Alma in Works (1959) I ii 496: In china none hold Women sweet, Except their Snags are black as Jett.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1846		Censor (London) 18 Jan. 6/2: [H]e actually would undertak e to remove snaggs as he called teeth.
1859		Matsell Vocabulum.
1865		Leaves from Diary of Celebrated Burglar 56/2: From our side of the water we had [...] George Appleby, alias ‘snags’ and his ‘stalls’.

2. (Aus./US ) a jagged tooth.

1933		J. Conroy Disinherited 166: He had only a few teeth left. ‘Gotta do some maneuverin’ t’ git my grub t’ where I can grind it with these snags.’.
1949		R. Park Poor Man’s Orange 212: ‘Jeepers, what an awful-looking lot of clothes-pegs. Why don’t you get them out?’ ‘I was thinking of it,’ said Mumma. ‘A person can’t look their best with a mouthful of old snags.’.
1967		M. Braly On the Yard (2002) 9: Yank the bastards, Doc [...] Those snags have whipped me for a lot of action.