| Shady |
| Illegal |
| Verboten |
| Backdoor |
| Unlawful |
| Forbidden |
| Not legal |
| Proscribed |
| Prohibited |
| Not lawful |
| Not allowed |
| Black-market |
| Unauthorized |
| Not permitted |
| Disapproved of |
| Under the table |
| Like gunrunning |
| Against the law |
| Like some stills |
| Like hanky-panky |
| Against the rules |
| Like some romances |
| Contrary to morality or convention |