indomitable
adj.adj. describing someone who is very strong and never gives up, even when things are very difficult. You use this to talk about a person's spirit or courage.
adj. impossible to subdue or overcome; showing great courage and determination. Often used to describe a person's spirit or a force that cannot be resisted.
She has an indomitable spirit that helps her through every challenge.
Despite the heavy snow and broken equipment, the team's indomitable will to reach the summit never wavered.
The city's indomitable character was forged during the long siege, as its citizens refused to surrender despite the overwhelming odds and dwindling supplies.
From Late Latin indomitābilis, from in- (“not”) + domitō, frequentative of domō (“to tame”). By surface analysis, in- + domitable.