Green’s Dictionary of Slang

1. an attractive or admirable person.

1967–8

Baker et al. CUSS 212: Tough A sexually attractive person, male [...] female. A socially adept person. A quick or witty person. A well-dressed person.

2. (US black) money gained from theft or confidence tricks that is used for buying drugs.

1971

H.E. Roberts Third Ear n.p.: tough n. money gained illegally and used to buy drugs.