Green’s Dictionary of Slang

1. (US tramp) one who maintains a respectable appearance as a mask for criminality.

1931

Irwin Amer. Tramp and Und. Sl. 81: Fronter.– One who maintains an apparently innocent enterprise or store as a blind behind which bootleggers or other lawless persons may work without fear of molestation.

2. (UK/US black) a show-off, a fake.

1994		C. Major Juba to Jive.
2008		R. Price Lush Life 341: In a world of fronters he thought with his hands and dealt with the fallout later .
2015		J. Spades ‘Twerk’ 🎵 You in front of some real bosses, no fronters.