Tusken is a slur used to describe Somalians in a derogatory way. Star Wars reference to the Tuscan Raiders, nomadic desert dwellers that no one likes.
The word Tusken is a racial slur that has been used historically to degrade and dehumanize somalians. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to somalians. If you are unsure about whether or not it is appropriate to use the word Tusken, it is best to err on the side of caution and avoid using it in any situation.