Green’s Dictionary of Slang

1. any form of money paid over in advance.

1925		in Collier’s 8 Aug. 30: Expense money [...] ‘front’ money [HDAS].
1935		Sun (N.Y.) 19 Feb. 28/2: ‘Front money’ is advance commission to a salesman.
1973		E. Bunker No Beast So Fierce 119: I had thought of asking him for ‘front’ money for weapons.
1989		A. Vachss Hard Candy (1990) 82: We’d split the front money too.
1991		in J. Breslin Damon Runyon (1992) 117: Dugan [...] interviewed arsonists, all of whom wanted either a piece of the insurance or front money.
2002		T. Hauser Inside the Ropes with Jesse Ventura 69: You can do a book deal with no front money and it can still make a ton of money.

2. (US) money to show and impress others.

1935		A.J. Pollock Und. Speaks 42/2: Front money, money used to put on a good appearance.
1940		J.H. O’Hara Pal Joey 78: She would have the front money.

3. (drugs) money advanced to a dealer for the purchase of drugs.

1969		R.R. Lingeman Drugs from A to Z (1970) 98: front [...] also front money. Payment in advance for drugs.
1975		E. Torres Carlito’s Way 58: Have fifty ready for him — front money.