Indomitable Fortitude is a term that describes an unyielding strength of character and determination. It is often used to describe someone who has the courage and perseverance to overcome any obstacle. The term can also be used to describe a situation or event that requires great courage and strength to endure. In this crossword, the term is represented by the word 'GRIT', which is defined as courage and resolve in the face of difficulty. GRIT is a four-letter word that perfectly encapsulates the meaning of Indomitable Fortitude.