POTENT

[adjective]Something that is potent is very powerful, strong, forceful or effective.Surprise remains the terrorists' most potent weapon.The Berlin Wall was a potent symbol of the Cold War.Farmers are still a potent political force in France.In her speech she presented a potent (= persuasive) argument for increasing taxes.He drowned in the hotel swimming pool after drinking a potent mix of whisky, gin and vodka.This is a very potent drug and can have unpleasant side-effects.