Turco is a slur used to describe Arabs in a derogatory way. Used primarily in Spanish-speaking countries, and South America in particular as a derogatory term for people of Arabic descent. It means "Turk," a much-hated nation by other Arabic states, in Spanish.
The word Turco is a racial slur that has been used historically to degrade and dehumanize arabs. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to arabs. If you are unsure about whether or not it is appropriate to use the word Turco, it is best to err on the side of caution and avoid using it in any situation.