Mat

Mat (Russian: мат; матерщи́на / ма́терный язы́к) is the term for strong obscene profanity in Russian and some other Slavic language communities. Use of mat is censored in the media and use of mat in public constitutes a form of disorderly conduct, punishable under article 20.1.1 of the Offences Code of Russia, although it is only enforced episodically, in particular due to vagueness of the legal definition. Despite the public ban, mat is used by Russians of all ages and in all social groups, with particular fervor in male-dominated military and the structurally similar social strata.

Mat in The Gladiator
In an Alternate where the Soviet Union won the Cold War, Russian slang known a "Mat" developed into a separate dialect of the language. While common among Russians, especially ex-Zeks, it was not advisable for non-Russians to use it.

When comrade Terekhova visited Annarita Crosetti's Russian language course, her use of Mat was barely understandable and what Crosetti did understand made her want to blush.