sang-froid vs calmness

sang-froid and calmness both are nouns.

Word	Noun	Adjective	Verb	Adverb
sang-froid	Yes	No	No	No
calmness	Yes	No	No	No

As nouns, calmness is a hypernym of sang-froid; that is, calmness is a word with a broader meaning than sang-froid:

Other hypernyms of sang-froid include calm, composure, equanimity.

sang-froid (noun)	calmness (noun)
great coolness and composure under strain	steadiness of mind under stress
	a feeling of calm; an absence of agitation or excitement
	an absence of strong winds or rain