1. To refuse to change one's position, opinion, or decision despite pressure or opposition
She decided to stand firm on her principles despite criticism.
Ela decidiu manter-se firme em seus princípios apesar das críticas.
2. To remain steadfast and resolute in the face of adversity or challenge
The team stood firm against their rivals' aggressive tactics.
O time manteve-se firme contra as táticas agressivas de seus rivais.