1. Firmly loyal, committed, or devoted to a person, cause, or belief; unwavering in allegiance or support
She remained steadfast to her principles despite pressure to compromise.
Ela permaneceu fiel aos seus princípios apesar da pressão para fazer concessões.
2. Constant and unchanging in one's commitment or devotion
He was steadfast to his promise to always support his family.
Ele foi firme em sua promessa de sempre apoiar sua família.