Green’s Dictionary of Slang

heavy-duty adj.

[SE heavy-duty, hard-wearing]

1. [1930s+] (orig. US) intense, serious, committed.

2. [1970s+] (US) tough, unpleasant.

3. [1970s+] (US) terrific, first-rate.

4. [1980s+] (US) deeply committed, heavily involved.

5. [1980s+] (US drugs) strongly addictive.

6. [1990s] (US) fat, overweight.