1. to go against someone or something; to challenge someone or something; to show disrespect for something or someone

1. John has decided not to go to college. It’s a bad decision on his part. It flies in the face of all common sense.

2. If you marry someone your parents disapprove of so much, it will fly in the face of everything they want for you.

3. His explanation flies in the face of the evidence.

4. You had better not fly in the face of the committee.

5. This is an argument that seems to fly in the face of common sense.