Aggression and aggressiveness are closely related—both can mean hostile or destructive behavior or actions—but in practical usage, especially in North America, they have differentiated. Aggression is more extreme, usually involving maliciousness or even hostility that can take the form of violent action. Aggressiveness is rarely malicious or violent. Instead, the word connotes assertiveness and drive—a more figurative aggression. It is more of an attitude, and it may even be viewed as a positive character attribute in the workplace or on a sports field, for instance. Aggression involves behaviors that would not be considered acceptable in these settings.
Aggression is the older form. It came to English from French around the 17th century and in early use usually referred to attacks and assaults.1 By the 19th century, it developed the primarily American sense energy showing drive or assertiveness.2 Aggressiveness came about in that century probably out of a need to separate this newer sense from the older ones for clarity’s sake.3
Aggressiveness is especially common in American and Canadian English, while the above distinctions aren’t always borne out in writing from outside North America, where aggression is used more broadly to cover both violent hostility and the type of boldness that benefits sports players and businesspeople.
With the following examples, note how aggressiveness is a neutral or even positive thing while aggression is problematic:
Cook has already made his mark on the company, encouraging efficiency and market aggressiveness. [Forbes]
So far, it’s seemed that violence in video games may spur aggression in players. [Washington Post]
The party’s aggressiveness against the Opposition’s campaign was articulated by Union minister Rajiv Shukla. [Daily Mail]
Some use aggression as an outlet, which can be a challenge for parents to deal with if they also want to be a disciplinarian. [Globe and Mail]
He adds that the deliberate shaved-head look conveys aggressiveness, competitiveness and shows “willingness to stand against social norms.” [Wall Street Journal]
Doctors are increasingly the target of verbal and physical aggression from colleagues and patients’ relatives, as well as from patients. [Australian]