Simple Definition:

Prejudice is a preconceived [created before there’s any evidence of it] opinion or attitude towards someone or something, typically based on limited information or stereotypes. Prejudice often leads to unfair treatment or discrimination [treating someone differently because of their race, gender, or religion]. For example, if someone believes that all people from a certain country are dishonest, they might treat individuals from that country with suspicion or dislike.

Very Simple Definition:

Prejudice is when someone doesn’t like or treats someone differently because of how they look or where they come from. For example, if someone doesn’t want to be friends with someone because they have a different skin color, that’s prejudice.