1. A decision made by one party without consultation or agreement from other interested parties
The company made a unilateral decision to close the factory without consulting employees.
A empresa tomou uma decisão unilateral de fechar a fábrica sem consultar os funcionários.
2. In legal or diplomatic contexts, an action taken by one side independently
The government announced a unilateral decision to withdraw from the treaty.
O governo anunciou uma decisão unilateral de se retirar do tratado.