Step 1: Definition:
Prejudice means a preconceived, usually negative, opinion or attitude held about a person or group, commonly based on their caste, religion, gender, region or ethnicity.
Step 2: Key feature:
It is formed without adequate knowledge, direct experience, or reasoning about the specific individual, and is typically rigid, resistant to change even when contrary evidence is presented.
Step 3: Consequence:
Because it pre-judges people based on group stereotypes rather than their actual qualities, prejudice frequently underlies discriminatory behaviour towards members of the targeted group.
Final Answer:
Prejudice is a rigid, unfounded, usually negative pre-judgment about people based on their group identity, which often leads to discrimination.