1. Going beyond what is right or proper; overstepping due bounds; impertinent
It would be presumptuous of me to assume I know what you're thinking.
Seria presunçoso da minha parte assumir que sei o que você está pensando.
2. Characterized by or resulting from immoderate ambition, presumption, or arrogance
His presumptuous behavior at the meeting alienated everyone.
Seu comportamento presunçoso na reunião alienou todos.