Prejudice refers to pre-judgement, i.e., an opinion made in advance. Prejudice refers to pre-thought opinions or attitudes held by members of one group towards another.
Prejudice may be either positive or negative. A prejudiced person’s pre-thought views r are .generally based on hearsay rather than on direct evidence. This word is generally used for negative pre-judgements.
On the other hand, an opinion is a judgment about someone or something, not necessarily based on fact and knowledge.