Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.
Class VI. Words Relating to the Sentient and Moral PowersSection II. Personal Affections
4. Contemplative Affections
871. [Absence of Wonder.] Expectance.
IMPERTURBABILITY. imperturbableness, imperturbation, sang-froid [F.], calmness, unruffled calm, coolness, coldbloodedness, hardheadedness, steadiness, lack of nerves, want of imagination, practicality.
nothing out of the ordinary.
IMPERTURBABLE, nerveless, cool, coolheaded, unruffled, calm, steady, hardheaded, practical, unimaginative.
common, ordinary (habitual) [See Habit].