a spirit that cannot be subdued or overcome, as persons, will, or courage; unconquerable: an indomitable warrior.
It is shown when a courageous person and his principles are pitted against overwhelming odds.
1.He wouldn't give up because of his Indomitable Spirit.
2.A serious student of Tae Kwon Do will at all times be modest and honest. If confronted with injustice, he will deal with the belligerent without any fear or hesitation at all, with indomitable spirit, regardless of whosoever and however many the numbers may be.