Fun fact: The #German word for hangover is "Kater". But "Kater" has a second meaning: tomcat, i.e. a male cat.

What does a hangover have to do with a cat?

Nothing.

It's kind of a malapropism for "Katarrh" (engl. "catarrh"), a similar-sounding word that was once used for all kinds of inflammations, from before medical science was a thing.

For the same reason German speakers use "Muskelkater" ("muscle tomcat") when they mean muscle soreness, especially DOMS.

#linguistics