fortitude vs courageousness

fortitude and courageousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
fortitude	Yes	No	No	No
courageousness	Yes	No	No	No

As nouns, courageousness is a hypernym of fortitude; that is, courageousness is a word with a broader meaning than fortitude:

fortitude: strength of mind that enables one to endure adversity with courage
courageousness: a quality of spirit that enables you to face danger or pain without showing fear

Other hypernyms of fortitude include natural virtue, braveness, bravery, courage.

fortitude (noun)	courageousness (noun)
strength of mind that enables one to endure adversity with courage	a quality of spirit that enables you to face danger or pain without showing fear