The phrase "old prejudices" refers to biased opinions or unfair judgments that have been held by people for a long time, often based on factors such as race, gender, or religion. Full definition
How does such grace serve to dissolve, or prevail over, the church - dividing vestiges of old prejudices, misunderstandings and hostilities? (religion-online.org)
In schools across the country, we're seeing results that smash old prejudices about what poor students can achieve. (gatesfoundation.org)
Two parties encumbered by the same old prejudices; straitjacketed by the same old ideologies. (politics.co.uk)