Impassivity is a related term of imperturbability.
As nouns the difference between impassivity and imperturbability
is that impassivity is the state of being impassive while imperturbability is a state of calm, unruffled self-assurance; aplomb, composure.
impassivity
English
Noun
(-)
the state of being impassive
imperturbability
English
Noun
(-)
A state of calm, unruffled self-assurance; aplomb, composure.
Related terms
* imperturbable