After the 18th amendment was passed, Prohibition failed to produce an alcohol-free society, and many citizens continued to consume alcohol in underground nightclubs and bars known as speakeasies or by what other name?

Blind pigs

Explanation:

Speakeasies were also called blind pigs. The original name "Speakeasies" comes from the phrase "Speak easy", alluding at the fact that people who visited these places had to be secretive about them.

These places were often operated by local business owners in small towns, while in large towns and cities, they were for the most part in the hands of organized crime.