1. to stay loyal, committed, or unwavering in one's position, beliefs, or purpose despite difficulties or opposition
Despite the criticism, she remained steadfast in her commitment to the project.
Apesar das críticas, ela manteve-se firme no seu compromisso com o projeto.
2. to continue to be resolute and determined without changing course
The team remained steadfast in their efforts to win the championship.
O time manteve-se firme nos seus esforços para ganhar o campeonato.