Bigot, as Morgan Horse answered, has pretty much exactly the denotation you want. However, it also has connotations that make it less than ideal for some applications:
- In my experience, it connotes conscious, and even enthusiastic, discrimination.
- It's usually read as very perjorative.
- Because bigot is a noun, describing someone as a bigot suggests that their discriminatory behavior is an essential character trait.
In places where these connotations may be undesirable—for example, in sociology research, where the discriminatory behavior under investigation is often unconscious, and researchers tend to avoid making explicit moral judgments about their subjects—the more vague but more neutral adjective biased is sometimes used instead, its meaning being made clear from context.