I think it is a bit muddled as the term we use for viking today comes from the verb (in modern Norwegian) "å dra i viking" which is a term used back in the days

I think it is a bit muddled as the term we use for viking today comes from the verb (in modern Norwegian) "å dra i viking" which is a term used back in the days as seen from the sagas. I see it is mentioned in the article too. However it could be that it originally described a person from Viken, but it was also actively used as a verb a thousand years ago in western Norway. Being Norwegian myself I've actually never connected it with the word vik which is also seen in English often as the word wick at the end of place names.