coolness vs imperturbability

coolness and imperturbability both are nouns.

Word	Noun	Adjective	Verb	Adverb
coolness	Yes	No	No	No
imperturbability	Yes	No	No	No

As nouns, coolness and imperturbability are synonyms defined as:

Other synonyms of coolness include imperturbableness.

coolness (noun)	imperturbability (noun)
the property of being moderately cold	calm and unruffled self-assurance
a lack of affection or enthusiasm
fearless self-possession in the face of danger
calm and unruffled self-assurance