1. To pay for something in advance, before receiving goods or services
You need to pay upfront for the hotel reservation.
Você precisa pagar antecipadamente pela reserva do hotel.
2. To pay the full amount at the beginning of a transaction rather than in installments
The contractor requires customers to pay upfront before starting the project.
O contratante exige que os clientes paguem adiantado antes de começar o projeto.