Green’s Dictionary of Slang

1. a piece of dried mucus [? SE boggy, soft, spongy; thus the consistency of such pieces of mucus].

1960		G.W. Target Teachers (1962) 17: She had this dirty great bogey up her nose.
1967		letter 4 Nov. in M. Amis Experience (2000) 20: I’ve considered retaliation – putting bogies [nose-pickings] in his coffee.
1983		(con. 1940s) D. Nobbs Second From Last in the Sack Race 175: Mr Pick-Nose was carried off by the bogey man.
1999		Observer 3 Oct. 8: I caught someone flicking bogeys into another prisoner’s pudding.
2000		N. Griffiths Grits 273: When yer off yer box on heroin yer might gerroff on pickin bogeys out yer nose for owers on end.
2011		S. Kelman Pigeon English 157: I got the best bogey I could find and put it in the empty wrapper.
2012		J. Fagan Panopticon (2013) 59: He rams his index finger up his nose [...] inspects the bogey and then flicks it away.

2. a nickname given to a man with prominent, wide nostrils.

1984

Partridge DSUE (8th edn) 110/1: C.20.