bias against (someone or something)
A prejudice against someone or something. That teacher just seems to have a bias against me—she never calls on me in class, and she grades my papers so harshly. My father has a bias against that company because he dislikes its outspoken CEO. The bias against hiring women that exists in this company is painfully obvious.
bias someone against someone or something
to prejudice someone against someone or something. Please avoid biasing everyone against me. One bad experience biased all of us against that brand of sausage.