dismiss (someone or something) out of hand
1. To reject, deny, or refuse to listen to someone or something right away, without due discussion or consideration. She's so stubborn that she just dismissed my suggestion out of hand. We'd like to try some alternative treatments. They're a bit unconventional, but please don't dismiss them out of hand. The police dismissed me out of hand when I went to report the crime.
2. To terminate someone's employment without due discussion or consideration. The company dismissed him out of hand when it came to light that he had been accepting bribes. The senator dismissed her aide out of hand for what she said to the press.