go against (someone or something)
1. To oppose, disagree with, or compete against someone or something. I can't take money from a charity like that, it goes against all of my core principles. You'll be going against a state champion in the next match, so you'll have to give it everything you've got!
2. To be or signal a disadvantage or undesired outcome for someone or something. The senator's uncouth comments are certain to go against him in his re-election campaign. Though we thought we had an airtight legal argument, but the court case ultimately went against us.