de·ci·sive 
/dɪˈsaɪsɪv/ adjective
/dɪˈsaɪsɪv/ adjective [more decisive; most decisive] 1 : able to make choices quickly and confidently
▪ You must be decisive and persistent to succeed in this competitive field. ▪ I stood there wondering what to do, but my sister was more decisive and immediately went to the phone. ▪ a decisive leader ▪ In emergency situations, one must be able to take decisive action. [=to act quickly and with confidence] — opposite indecisive 2 : causing something to end in a particular way : determining what the result of something will be
▪ She cast the decisive [=deciding] vote. ▪ The fight ended with a decisive blow. ▪ the decisive battle of the war ▪ The poverty of his childhood played a decisive role in his adult life. ▪ The meeting is seen as a decisive step toward a peace treaty. ◊A decisive factor is a reason to make a particular choice or decision.
▪ The decisive factor [=deciding factor] was cost. ▪ His lack of experience was the decisive factor in my decision not to hire him. 3 : very clear and obvious
▪ a decisive victory/win/advantage
▪ You must be decisive and persistent to succeed in this competitive field. ▪ I stood there wondering what to do, but my sister was more decisive and immediately went to the phone. ▪ a decisive leader ▪ In emergency situations, one must be able to take decisive action. [=to act quickly and with confidence] — opposite indecisive
▪ She cast the decisive [=deciding] vote. ▪ The fight ended with a decisive blow. ▪ the decisive battle of the war ▪ The poverty of his childhood played a decisive role in his adult life. ▪ The meeting is seen as a decisive step toward a peace treaty. ◊A decisive factor is a reason to make a particular choice or decision.
▪ The decisive factor [=deciding factor] was cost. ▪ His lack of experience was the decisive factor in my decision not to hire him.
▪ a decisive victory/win/advantage
— de·ci·sive·ly adverb
▪ You must be able to act decisively to succeed in this competitive field. ▪ She decisively rejected their proposal.
▪ You must be able to act decisively to succeed in this competitive field. ▪ She decisively rejected their proposal.
— de·ci·sive·ness noun [noncount]
▪ The job requires decisiveness [=decision] and persistence.
▪ The job requires decisiveness [=decision] and persistence.
