Ruthless/ˈruːθləs/ Definition 1 of 1Pro Tip 1/3Negative Emotion Ruthless often implies negative feelings and is used to criticize. Her ruthless decision to close the factory upset many. Pro Tip 2/3Power and Control Ruthless is commonly used to describe actions in positions of power or competition. He climbed the corporate ladder through ruthless ambition. Pro Tip 3/3Intensity Ruthless behavior is extreme and shows a lack of moderation. The coach's ruthless training regimen led to many victories.