um and aah
um and ah
To be hesitant or indecisive, especially when speaking out loud about a decision. "Um" and "ah" are common filler words used by habit or when one is deciding what to say. Try not to um and ah so much when you're considering a counter-proposal—it's not professional. It felt like that guy ummed and ahed for five minutes before he gave me his order. Which was a burger and fries, by the way.
ˌum and ˈaah (about something)(also ˌhum/ˌhem and ˈhaw less frequent) (informal) speak but say nothing important because you need more time to think about a problem, matter, etc: He ummed and aahed for about half an hour and then finally said he would lend me the money. ♢ After a lot of umming and aahing, he finally said yes to the plan.
Um, aah, etc. are sounds that people make when they hesitate or do not know what to say next.