Deciso vs. decisivo
In Italian, the English word "decisive" can be translated as either deciso or decisivo, but they serve different functions. Deciso typically describes a person's character or intent (being determined), while decisivo describes the importance of an event or factor (being crucial/determining).
Deciso
A2This adjective describes a person who is resolute, determined, and firm in their will. It can also describe an action performed with confidence and lack of hesitation. Use deciso when you want to say someone has made up their mind or has a strong personality.
Marco è molto deciso a comprare quella casa.
(Marco is very determined to buy that house.)
Ha risposto con un tono deciso.
(He answered with a firm tone.)
Ci serve un leader più deciso in questa situazione.
(We need a more resolute leader in this situation.)
Camminava con passo rapido e deciso.
(She was walking with a quick and firm step.)
Ormai sono deciso, parto domani.
(I have made up my mind, I am leaving tomorrow.)
Decisivo
B1This adjective describes a thing, event, or person that settles a matter or produces a final result. It implies that something is game-changing, crucial, or determining. Use decisivo when referring to the cause that dictates the outcome.
Il tuo intervento è stato decisivo per la vittoria.
(Your intervention was crucial for the victory.)
Questo è un momento decisivo per la nostra carriera.
(This is a decisive moment for our career.)
Hanno segnato il punto decisivo all'ultimo secondo.
(They scored the winning point at the very last second.)
La prova testimoniale non è stata decisiva.
(The witness evidence was not conclusive.)
Il ruolo del portiere è stato decisivo nella partita.
(The goalkeeper's role was the determining factor in the match.)
Summary
To summarize, use deciso regarding internal motivation (being resolute/firm) and decisivo regarding external influence (being crucial/conclusive). A person is deciso if they know what they want; a person or event is decisivo if they determine the final outcome.