The word "harum-scarum" refers to a person who is reckless, impulsive and lacking in caution. Some synonyms for this word include impetuous, devil-may-care, wild, rash, heedless, careless, thoughtless, and unthinking. Each of these synonyms signifies a similar behavioral trait of being hasty and careless without much thought or consideration of consequences. These words can be used interchangeably with "harum-scarum" in a variety of contexts. Whether it's describing a person's personality or actions, these synonyms are useful in communicating the same message in different ways.