Rowdytum, das

This term for hooliganism was one of the most comical expressions of East German communism, though the implications were hardly funny for the person labelled as der Rowdy. The East German courts convicted and imprisoned protesters for das Rowdytum, a catch-all offence that embraced almost any authority-defying behaviour in a public place.

This Anglicism harks back to the 19th century - the days of Karl Marx - when a rowdy was indeed a disorderly young man, as for example in a passage from the Nottingham Date Book (1852): ....

By the 20th century, it had been used so often as a figure of speech that its meaning was much weakened: a rowdy child is merely one who is playing vigorously, and a rowdy party is one where the music is loud: in both cases the implication is that I am annoyed at the noise (but could be over-sensitive).

Since German has retained the old sense, and only the old sense, the word is a false friend. The Duden Fremdwörterbuch no longer has das Rowdytum (if it ever had it) and only has der Rowdy. Das Rowdytum, which has acquired a standard German nominalizing suffix, is capitalized, given neuter gender and inflected with -s- in the genitive.