köken: Old Swedish forrædheri, likely borrowed from unattested Middle Low German *vorrederie. By surface analysis, förrädare + -eri. Cognate of Danish forræderi, German Verräterei.
köken: Etymology tree Latin perfidus Proto-Indo-European *-yós Proto-Italic *-ios Old Latin -ios Latin -ius Latin -ia Latin perfidialbor. Polish perfidia Learned borrowing from Latin perfidia.
köken: Etymology tree Latin perfidus Proto-Indo-European *-yós Proto-Italic *-ios Old Latin -ios Latin -ius Latin -ia Latin perfidia From perfidus + -ia.