mettle vs courageousness

mettle and courageousness both are nouns.

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

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

mettle: the courage to carry on
courageousness: a quality of spirit that enables you to face danger or pain without showing fear

Other hypernyms of mettle include braveness, bravery, courage.

mettle (noun)	courageousness (noun)
the courage to carry on	a quality of spirit that enables you to face danger or pain without showing fear