'Impassiveness' definitions:

Definition of 'impassiveness'

From: WordNet
noun
Apathy demonstrated by an absence of emotional reactions [syn: emotionlessness, impassivity, impassiveness, phlegm, indifference, stolidity, unemotionality]

Definition of 'Impassiveness'

From: GCIDE
  • Impassive \Im*pas"sive\, a. Not susceptible of pain or suffering; apathetic; impassible; unmoved. [1913 Webster]
  • Impassive as the marble in the quarry. --De Quincey. [1913 Webster]
  • On the impassive ice the lightings play. --Pope. -- {Im*pas"sive*ly}, adv. -- {Im*pas"sive*ness}, n. [1913 Webster]

Definition of 'impassiveness'

From: GCIDE
  • impassiveness \im*pas"sive*ness\ n. an absence of emotion.
  • Syn: apathy, impassivity. [WordNet 1.5]