Attack/əˈtæk/ Definition 1 of 5Pro Tip 1/3Physical Harm Used to describe a harmful action that can cause damage or injury. The knights planned their attack at dawn. Pro Tip 2/3Requires Defense Implies a need for defense or protection from the one attacked. The fortifications were strengthened to ward off attacks. Pro Tip 3/3Warfare Context Often used in military contexts to describe combative actions between groups. The platoon coordinated an attack against the insurgents.