Green’s Dictionary of Slang

1. (also miff, nif) to smell unpleasantly, to stink.

1890		Sporting Times 8 Nov. 1/5: The Staff of the Sporting Times on a Car Representing a Visit to Shifter [...] in Holloway Castle. Banner of Toke. Banner of Streamy. Banner of Duff. Banner of Spotted Baby. Banner of Thick. Banner of two Doorsteps [...] Banner of Oh Don’t it Niff.
1899		Crissie 15: ‘I know you nif a bit, but don’t you fret yourself’.
1901		Boy’s Own Paper 24 Aug. 751: Jinks blew his bull’s-eye out, and it simply niffed all over the rooms.
1916		G. Squiers Aerbut Paerks, of Baernegum 14: Strike, they ’aven’t ’arf got a few animiles, and sum on ’em don’t ’arf miff.
1949		Wodehouse Mating Season 26: The animal niffed to heaven.
1956		‘Charles Raven’ Und. Nights 198: He snored like a bassoon and niffed like a badger.
2003		N. Griffiths Stump 132: [of a wound] Beginnin to niff a bit as well, to be honest with yis. That can’t be right.

2. to smell something, usu. an unpleasant smell.

1906		Marvel 5 May 422: I niffed it meself.
1915		T. Burke Nights in Town 126: ‘Niff it?’ she jerked in allusion to the stew.
1943		R. Llewellyn None But the Lonely Heart 31: Give your guts a proper treat it did, to go past and niff.
1968		A. Burgess Enderby Outside in Complete Enderby (2002) 307: Niff that juicy couscous. Yummiyum.