Green’s Dictionary of Slang

up front adv.

also in front
[SE/front v.3 ]

1. [1950s+] in advance, esp. of money paid for illegal activities, e.g. drug purchases.

2. [1950s+] openly, without deception.

3. [1960s+] (orig. US black) first, at the start.

4. [1970s] fig., in the foreground.

5. (Aus.) in profit.