impassive
/(ˌ)im-ˈpa-siv/
adjective
giving no sign of feeling or emotion : expressionless
unsusceptible to or destitute of emotion : apathetic
unsusceptible to physical feeling : insensible
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. stoic implies an apparent indifference to pleasure or especially to pain often as a matter of principle or self-discipline.