coolness
US /ˈkuːl.nəs/
UK /ˈkuːl.nəs/

1.
fraîcheur
the quality or state of being cool (low in temperature)
:
•
The coolness of the evening air was refreshing.
La fraîcheur de l'air du soir était rafraîchissante.
•
She enjoyed the coolness of the shade on a hot day.
Elle appréciait la fraîcheur de l'ombre par une chaude journée.
2.
coolitude, classe, style
the quality of being fashionable, sophisticated, or impressive
:
•
His new car has a certain coolness about it.
Sa nouvelle voiture a une certaine classe.
•
The band's effortless coolness attracted a large following.
La coolitude naturelle du groupe a attiré un large public.
3.
sang-froid, calme, sérénité
calmness and self-control, especially in difficult situations
:
•
He maintained his coolness under pressure.
Il a gardé son sang-froid sous la pression.
•
Her coolness in the face of danger was admirable.
Son sang-froid face au danger était admirable.