To be specific, a racist is someone who believes that a certain race, colour, nationality etc is inferior to themself or their race, colour or nationality. If someone acts like this, they would be acting racist or they probably would be a racist. This can also be called racism. Racism is different from sexism, which is when on gender believes their gender is superior to the opposite gender. Like if a man says that women are weak or if a women said men are stupid whoever said that would be a sexist. Sorry if you know that already!