1. to remain loyal, committed, or resolute in one's beliefs, decisions, or principles despite difficulties or opposition
She remained steadfast in her commitment to the project despite numerous setbacks.
Ela manteve-se firme em seu compromisso com o projeto apesar dos muitos obstáculos.
2. to not change one's position or course of action; to be unwavering
He was steadfast in his refusal to compromise his values.
Ele foi inabalável em sua recusa de comprometer seus valores.
3. to be constant and reliable in behavior or loyalty
Their friendship remained steadfast throughout the years.
Sua amizade permaneceu constante ao longo dos anos.