Prejudice is any preconceived opinion, judgement or feeling whether positive or negative formed beforehand without the knowledge of facts. It is a judgement based of sentiments.
"I'd like to sue the judge of his prejudice in handling the case of the protesters."
Prejudice and prejudiced are part of the same word family. The meaning is that you form an opinion based on pre-conceived ideas about a person or thing, rather than on actual experience or facts. Prejudice is the noun form and prejudiced is the adjective form.
“John has a prejudice against immigrants even though he has never met someone who was born in another country.”
“John is prejudiced against immigrants even though he has never met someone who was born in another country.”