Impassive

прилагательное 1) [устаревшее] смотри значение impassible 2) невозмутимый, бесстрастный; безмятежный, спокойный Синоним(ы): apathetic, indifferent, insensible, phlegmatic, dispassionate, passionless 3) невосприимчивый, невпечатлительный Синоним(ы): unimpressionable

Большой англо-русский словарь

Impassive

adjective 1. a. archaic unsusceptible to pain b. unsusceptible to physical feeling; insensible c. unsusceptible to or destitute of emotion; apathetic 2. giving no sign of feeling or emotion; expressionlessimpassively adverbimpassiveness nounimpassivity noun Synonyms: impassive, stoic, phlegmatic, apathetic, stolid mean unresponsive to something that might normally excite interest or emotion. impassive stresses the absence of any external sign of emotion in action or facial expression Example: met the news with an impassive look. stoic implies an apparent indifference to pleasure or especially to pain often as a matter of principle or self-discipline Example: was resolutely stoic even in adversity. phlegmatic implies a temperament or constitution hard to arouse Example: a phlegmatic man unmoved by tears. apathetic may imply a puzzling or deplorable indifference or inertness Example: charitable appeals met an apathetic response. stolid implies an habitual absence of interest, responsiveness, or curiosity Example: stolid workers wedded to routine.

Merriam-Webster's Collegiate Dictionary