rasismo

Rasismo is a build, and a completely regular one: raso, race, plus -ism-, the doctrine suffix, plus the noun ending. The belief system built on race.

-Ism- is the machine that turns any root into the doctrine or movement attached to it, and it runs on borrowed roots and native ones alike: kapitalismo, komunismo, naciismo nationalism, Esperantismo the movement around this language itself. Its partner is -ist-, the person who holds the doctrine or does the job - so rasisto is a racist, rasisma is the adjective, and kontraŭrasisma is anti-racist, built with the preposition kontraŭ used as a prefix.

The suffix pair is not perfectly tidy, and pretending it is would mislead. Kristanismo is built on kristano, the believer, rather than the other way round; islamano is a Muslim built on Islamo, the religion. The countries and peoples article works through the asymmetries, which arose because the words arrived at different times from different languages rather than by design.

A note on the root. Raso in Esperanto is used of animal breeds as much as of human populations, and modern biology does not support race as a natural division of humanity in the way nineteenth-century writers assumed. Rasismo is the ideology that treats it as one, and the word is condemnatory in Esperanto exactly as it is in English.