harum-scarum 1 adv. , informal In a careless, disorderly or reckless way. Jim does his homework harum-scarum, and that is why his schoolwork is so poor.
harum-scarum 2 adj. , informal Careless, wild, or disorderly in one's acts or performance; reckless. Jack is such a harum-scarum boy that you can never depend on him to do anything right.