Bolita is a slur used to describe Bolivian in a derogatory way. Argentines refer to the poorer Bolivian immigrants who live in Argentina as "bolitas." It means "small balls" in Spanish.
The word Bolita is a racial slur that has been used historically to degrade and dehumanize bolivian. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to bolivian. If you are unsure about whether or not it is appropriate to use the word Bolita, it is best to err on the side of caution and avoid using it in any situation.