From Longman Dictionary of Contemporary Englishrotgutrot‧gut /ˈrɒtɡʌt $ ˈrɑːt-/ noun [uncountable] informalDFD strong cheap low-quality alcohol
Examples from the Corpus
rotgut• rotgut whiskey• Somebody passed a bottle of rotgut, the bottom of it.• So, you had to drink the rotgut, like Black Label or Falstaff. 