one who, or that which, flees from danger, duty, restraint, etc.; a fugitive.-the act of running away, esp. of a horse or teams; as, there was a runaway yesterday.-running away; fleeing from danger, duty, restraint, etc.; as, runaway soldiers; a runaway horse.-accomplished by running away or elopement, or during flight; as, a runaway marriage.-won by a long lead; as, a runaway victory.-very successful; accomplishing success quickly; as, a runaway bestseller.