Afixed attitude, belief, or emotion held by an individual about another individual or group that is based on faulty or unsubstantiated data is otherwise known as

Prejudice

Explanation:

In social psychology and sociology, a  prejudice is an opinion (which is usually unfavourable) that was formed before having any evidence and without any logical reason. This prejudice refers to feelings and attitudes or emotions that a person has about another person or group of people.

We can say that, in other words, a fixed attitude, belief or emotion held by an individual about another individual or group that is based on faulty or unsubstantiated date is known as a prejudice.