1. An action taken in advance to prevent something undesirable from happening; a measure taken to stop something before it occurs
The government took preemptive action to prevent the spread of the disease.
O governo tomou ação preventiva para impedir a propagação da doença.
2. In military or political contexts, an action taken to neutralize a potential threat before it materializes
The military launched a preemptive action against the enemy forces.
Os militares lançaram uma ação preventiva contra as forças inimigas.