Viking is a slur used to describe Norwegians in a derogatory way. Self explanatory
The word Viking is a racial slur that has been used historically to degrade and dehumanize norwegians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to norwegians. If you are unsure about whether or not it is appropriate to use the word Viking, it is best to err on the side of caution and avoid using it in any situation.