Definition: Fortitude is having bravery and resiliency, mental strength. It’s the ability to bear pain with steadfastness, spirit, nerve and guts. 

Etymology:  The English word “fortitude” was derived from the Latin words fortis, meaning strong or brave and fortitudo, meaning strength, manliness, firmness, or force. It was first used in the English language around the late 14th century, meaning courage, strong cardinal virtue, moral strength. Later in the 15th century, the word also meant great physical strength. Today it means mental and physical strength.

In a Sentence

The girl displayed great fortitude in standing up to the group of bullies that tormented her on a daily basis after school.

After the tornado ripped through the entire town, the residents showed their fortitude by pulling together to rebuild their community.

In addition to giving recruits instruction on how to be Marines, Boot Camp develops fortitude among the ranks through vigorous mental and physical training exercises.

Synonyms 

Courage, Bravery, Resiliency, Bravery, Backbone, Guts, Spirit

Antonyms 

Apathy, Fainthearted, Cowardly, Cowardice