This is the 999th most frequent Portuguese word.
estiver
"Estiver" is the third-person singular or "you" (formal) conjugation of the verb "estar" in the future subjunctive tense, meaning "is/will be" in hypothetical or uncertain future contexts.
The word 'estiver' is used in the subjunctive mood to express a hypothetical condition.
Se você estiver cansado mais tarde, podemos fazer uma pausa.
If you are tired later, we can take a break.
Here, 'estiver' indicates a subjunctive mood relating to a necessity or requirement.
É essencial que o documento estiver assinado antes da reunião.
It is essential that the document is signed before the meeting.
In this context, 'estiver' is used to express a potential situation in the future.