C2 the force or action of one object hitting another: The impact of the crash reduced the car to a third of its original length. The bullet explodes on impact (= when it hits another object).Energy, force and powerPower and intensity B2 a powerful effect that something, especially something new, has on a situation or person: The anti-smoking campaign had had/made quite an impact on young people. The new proposals were intended to soften the impact of the reformed tax system.Outcomes and consequences