Set your face against somebody/something
Definition 1 of 1
Pro Tip 1/3Emotional Weight
Conveys strong personal conviction against something, suggesting an unyielding stance. 
Despite the popularity of the idea, she set her face against it for moral reasons.
Pro Tip 2/3Figurative Meaning
It's a metaphorical expression, not about one's literal face, but one's firm attitude. 
He set his face against the unfair policies of the administration.
Pro Tip 3/3Serious Contexts
Used mainly in serious or formal discussions about opposition to ideas or actions. 
The committee set their face against the budget cuts due to potential risks.