From Proto-Indo-European *swé . This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term. whence -k? -ge like in the case of *mik?
*sek
accusative of *se-
Proto-West Germanic: *sik Old Frisian: sik ( likely borrowed ) Old Dutch: sich , sig ( only in Limburgish ) Middle Dutch: sich , sic , sik ( spread to other eastern dialects ) Dutch: zich ( standardized, likely reinforced by German sich ) Afrikaans: sig ( rare, obsolete ) Limburgish: zich Old High German: sih
Old Norse: sik
Icelandic: sig
Faroese: seg
Norwegian Bokmål: seg
Norwegian Nynorsk: seg
Jamtish: seg
Old Swedish: sik
Danish: sig
Old Norse: -sk ( passive verb suffix )
Icelandic: -st
Norwegian:
Norwegian Bokmål: -s
Norwegian Nynorsk: -st
Swedish: -s
Danish: -s
Gothic: 𐍃𐌹𐌺 ( sik )