1. A specific, fixed date or time by which a task must be completed, with no possibility of extension or ambiguity
The project has a definite deadline of March 31st.
O projeto tem um prazo definitivo de 31 de março.
2. A firm and clear time limit established for the completion of work or submission of materials
We need to meet the definite deadline for the proposal submission.
Precisamos cumprir o prazo definitivo para a apresentação da proposta.