Decidido vs. decisivo
While both decidido and decisivo are often translated as "decisive" in English, they distinguish between a person's determined attitude and the crucial impact of an event. Decidido describes someone who is resolute or unhesitating, whereas decisivo describes something that determines an outcome or is of high importance.
Decidido
B1This word is used to describe a person who is determined, resolute, or bold. It indicates that someone has made up their mind or acts without hesitation. While it encompasses the meaning of making decisions quickly, the focus is on the subject's firm will and lack of doubt.
Andrés está decidido a comprar esa casa mañana.
(Andrés is determined to buy that house tomorrow.)
Ella caminó hacia el escenario con paso decidido.
(She walked toward the stage with a decisive step.)
Necesitamos un líder decidido que no tema a los cambios.
(We need a decisive leader who is not afraid of change.)
El equipo se mostró decidido a ganar el campeonato.
(The team appeared determined to win the championship.)
Decisivo
B2This word describes a factor, moment, or action that is conclusive, crucial, or definitive. It refers to something that settles a dispute or determines the final result. When applied to a person, it usually implies that their specific involvement was the key factor that caused the outcome.
Su voto fue decisivo para aprobar la nueva ley.
(Her vote was decisive in passing the new law.)
Este es un momento decisivo para el futuro de la empresa.
(This is a decisive moment for the future of the company.)
El error del portero fue decisivo en el resultado final.
(The goalkeeper's error was decisive in the final result.)
Jugó un papel decisivo en la negociación de paz.
(He played a decisive role in the peace negotiation.)
Summary
Use decidido when you want to describe a person's attitude as bold, firm, or resolute (determined). Use decisivo when you want to describe a fact, event, or action that changes the course of events or determines the final outcome (conclusive/crucial).