ku: n., v., & int. --n. a soft murmuring sound like that of a dove or pigeon. --v. (coos, cooed) 1 intr. makethe sound of a coo. 2 intr. & tr. talk or say in a soft or amorousvoice. --int. Brit. sl. expressing surprise or incredulity. øøcooingly adv. [imit.]