The word fuck has probable cognates in other Germanic languages, such as German ficken (to fuck); Dutch fokken (to strike, to beget); dialectal Norwegian fukka (to copulate), and dialectal Swedish fokka (to strike, to copulate) and fock (penis). This points to a possible etymology where Common Germanic fuk– comes from an Indo-European root meaning "to strike", cognate with non-Germanic words such as Latin pugnus "fist". By reverse application of Grimm's law, this hypothetical root has the form *pug–.[citation needed] In early Proto-Germanic the word was likely used at first as a slang or euphemistic replacement for an older word for intercourse, and then became the usual word for intercourse. The original Indo-European root for to copulate is likely to be * h3yebh– or *h3eybh–, which is attested in Sanskrit यभति (yabhati), Russian ебать (yebat'), Polish jebać, and Serbian jebati, among others: compare the Greek verb οἴφω (oíphō) = "I have sex with", and the Greek noun Ζέφυρος (Zéphyros) (which references a Greek belief that the west wind Zephyrus caused pregnancy).