To drink alcohol and celebrate with other people in a noisy, lively, and often unrestrained way.
From Middle High German 'gar aus' (right out, completely), likely reinforced by Dutch 'caroosen.' It emerged in the 16th century as sailors and merchants borrowed the term from German drinking customs, gradually entering English through trade and military contact.
Carouse actually reflects the history of beer culture—it's a Germanic term that entered English when English soldiers came back from fighting on the continent and brought home the German tradition of drinking 'gar aus'—completely finishing the cup!
Complete word intelligence in one call. Free tier — 50 lookups/day.