A low, sustained, mournful cry, usually indicative of sorrow or pain. A similar sound: the eerie moan of the night wind. A complaint: his tiresome moans about his boss. To utter a moan or moans. To make a sound resembling a moan: A saxophone moaned in the background. To complain, lament, or grieve: an old man who still moans about his misspent youth. To bewail or bemoan: She moaned her misfortunes to anyone who would listen. To utter with moans or a moan.