Noogin is a slur used to describe Norwegians in a derogatory way. Columnist Mike Royko invented this one, claiming that there were no insults for Norwegians, because they were too well-liked and "nice." So he made this one up for a 1978 column.
The word Noogin 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 Noogin, it is best to err on the side of caution and avoid using it in any situation.