Also Romansh. Source: "Vornamen in der Schweiz. Prénoms en Suisse. I nomi in Svizzera. Prenoms in Svizra" (1993) published by the Association of Swiss registrars. https://rm.wikipedia.org/wiki/Rut_Plouda
Rut "Rutka" Laskier was a Jewish teenager from Poland who is best known for her 1943 diary chronicling the three months of her life during the Holocaust. She was murdered at Auschwitz concentration camp in 1943 at the age of 14. Her manuscript, authenticated by Holocaust scholars and survivors, was published in the Polish language for the first time ever in early 2006, drawing comparisons to the diary of Anne Frank instantly. It has since been released in numerous translations.
I understand it isn't pronounced the same as a less-polite verb, but it's spelled identically. If your child will ever be around English-speaking peers, I don't recommend it.
In Polish, the usual form would be Ruta, but even then this name is rarely used. Rut is however the Polish name for the biblical figure, whose name in English is Ruth.