pooh-pooh
1. noun An outright dismissal of some argument as being unworthy of consideration or debate. My idea could save the company millions, but I'm still expecting a pooh-pooh from the board of directors because of how radical it is.
2. verb To dismiss something outright, without any due consideration or debate. Don't pooh-pooh her idea before she's had the chance to explain the ins and outs of it! He's always pooh-poohing his assistant's ideas.