marked by defiant disregard for danger or consequences; "foolhardy enough to try to seize the gun from the hijacker"; "became the fiercest and most reckless of partisans"-Macaulay; "a reckless driver"; "a rash attempt to climb Mount Everest"
any warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk