Russian profanity
Mat, matershchina, mat language (Russian: мат; матерщи́на / ма́терный язы́к, romanized: matershchina / materny yazyk) are the Russian terms for highly vulgar, obscene, or profane language in Russian and some other Slavic language communities. A person who uses mat profusely is called matershchinnik (матерщинник).