croon Share definition Flag To speak, sing, moan, or hum in a soft, gentle, intimate, soothing, or murmuring manner, particularly when adapting to an amplification system or using an echoing effect. The mother was crooning over the sick child to help her fall asleep. croon by Steven January 23, 2004 0 0 Get merch Get the croon mug. Buy Now — $32.95 See more merch