What is "six o'clock swill"

n. (context Australia NZ historical English) The last-minute rush to buy alcohol at a bar before it closed at 6pm.

The six o'clock swill was an Australian and New Zealand slang term for the last-minute rush to buy drinks at a hotel bar before it closed. During a significant part of the 20th century, most Australian and New Zealand hotels shut their public bars at 6 pm. A culture developed of heavy drinking during the time between finishing work at 5 pm and the mandatory closing only an hour later.