Wikipedia
Perkele
Perkele means devil in modern Finnish and is used as a rude profanity. Some researchers consider Perkele an original name of Ukko, the chief god of the Finnish pagan pantheon but this view is not shared by all researchers. There are related words in other Balto-Finnic languages: in Estonian, põrgu means hell, in Karelian perkeleh means an evil spirit.