Green’s Dictionary of Slang

tough adv.

[tough adj.]

1. [1920s+] intensely, enthusiastically, commitedly.

2. [1930s+] in an aggressive manner.

3. [1950s–60s] attractively.

4. [1990s+] resolutely.

In phrases

do it tough (v.)

[1940s] (Aus.) to suffer.

ride tough (v.) [1970s+] (US black)

1. to be intoxicated by a drug.

2. to be riding in a noteworthy car.