resolute and fearless
unflinching - firm
To ‘flinch’ is to grimace or recoil from pain or fear, so to be ‘unflinching’ is to not show any reaction at all. The word is most commonly used in a figurative way to express being steadfast and unyielding, even when faced with a very difficult or dangerous situation. It has only positive connotations as it is associated with moral fortitude and courage.
My boss has been there for me throughout the difficult and protracted court case. I can’t thank her enough for her unflinching support.
The soldier was awarded a medal for the unflinching courage he showed during the battle to retake the city.
It wasn’t easy to hear such a harsh critique of my work, but David is known for his unflinching honesty.