Chefur is a slur used to describe Balkan in a derogatory way. Comes from the same roots as "Kaffir", and is used in Slovenia as a derogatory term for anyone originating from one of the former Yugoslav republics.
The word Chefur is a racial slur that has been used historically to degrade and dehumanize balkan. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to balkan. If you are unsure about whether or not it is appropriate to use the word Chefur, it is best to err on the side of caution and avoid using it in any situation.