piętnować (Polish) comes from Polish piętno, from Old Polish piątno, from Proto-Slavic pętьno, from Proto-Slavic pęta, from Proto-Slavic pęti, from Proto-Balto-Slavic pínˀtei, from Proto-Indo-European (s)penh₁- — to twist; to weave.
piętnować (Polish): to condemn, to castigate, to denounce