throw one's hands up (in despair)
1. Lit. to make a gesture of throwing up one's hands indicating futility, despair, finality, etc. He threw his hands up in despair and walked away. She threw up her hands and fled.
2. Fig. to give up in despair. John threw his hands up in despair because they wouldn't let him see his brother in the hospital. Don't give up! Don't just throw up your hands!