Steadfastness is a related term of staunchness.
As nouns the difference between steadfastness and staunchness
is that steadfastness is loyalty in the face of trouble and difficulty while staunchness is property of being staunch.
steadfastness
English
Noun
Loyalty in the face of trouble and difficulty.
Steadfast resolution.
staunchness
English
Noun
(-)
Property of being staunch.