decisively

to achieve victory in a clear and undeniable way

to take action in a confident and determined way

to win against someone clearly and without doubt

to have a strong and conclusive effect on someone or something

to refuse to accept something in a firm and clear way

to influence the development of something in a conclusive way

to become involved in a situation in a way that is intended to have a conclusive result

often used for shaking one's head to indicate a clear 'no'