The word "carouse" is a rare example of an entire phrase being compressed into a single English word. It preserves, in fossilized form, a German drinking toast that English soldiers and travelers brought home from the taverns and military camps of 16th-century Central Europe, turning an imperative ("drain your glass!") into a verb for boisterous celebration.
The German phrase gar aus (trinken) means "(to drink) completely out" — that is, to empty your glass entirely. Gar is a German adverb meaning "completely" or "entirely" (still used in modern German, as in gar nicht, "not at all"), and aus means "out" or "empty." Together, gar aus! functioned as a toast equivalent to "bottoms up!" or "drain it!" — a command to drink your vessel dry before setting it down.
English encountered this phrase in the mid-16th century, a period of intense military and cultural contact between England and the German-speaking lands of the Holy Roman Empire. English mercenaries fought in the continental religious wars, English merchants traded in German cities, and English travelers encountered German drinking customs — which were, by wide reputation, formidable. The phrase garouse or carouse entered English initially as a noun meaning a full glass or a drinking bout, then rapidly became a verb meaning to drink deeply and celebrate noisily.
The transformation is linguistically fascinating. English speakers heard the German toast, reinterpreted it as a single word rather than a phrase, and then adapted it to English grammar. By the time Shakespeare was writing in the 1590s, "carouse" was fully established. In Othello, Iago urges Cassio to "carouse" to celebrate; in Hamlet, the king carouses with cannon fire marking each toast. The word had already broadened from the specific act of draining a glass to the general activity of convivial, heavy
The 16th and 17th centuries were a golden age for English borrowing of German drinking vocabulary. "Rouse" (as in a full bumper), "toast" (partly influenced by German customs), and various terms for drinking vessels and quantities entered English through the same channels of military and commercial contact. This vocabulary transfer reflected a genuine cultural exchange: German lands were famous — or infamous — for the quantity and intensity of their communal drinking, and English visitors adopted both the practices and the words.
"Carouse" developed the related forms "carousal" (a drinking party or riotous festivity) and "carouser" (one who carouses), both formed by standard English derivation. The word's semantic range expanded over time to encompass not just drinking but general revelry, festivity, and noisy celebration. One can carouse without alcohol, though the word retains an implication of excess and exuberance that connects it to its origins as a command to empty your glass.
The German source phrase gar aus also survives in modern German, though in a different context. "Jemandem den Garaus machen" means "to finish someone off" or "to put an end to someone" — preserving the core meaning of "completely out" but applying it to destruction rather than drinking. The English carouse, by contrast, kept its festive associations, becoming a word for life at its loudest and most convivial rather than at its end.