His impassiveness only seemed to encourage the crowd further.
From the time.com
It will be up to the senior players to show the coolness of character, focus and discipline that is needed to combat the impassiveness of the Crusaders.
From the nznewsuk.co.uk
Her manner, gracious and upfront, lies halfway between the hyper-feminine breathiness she offers up for TV talk shows and the tough, stony-faced impassiveness she displays on the court.
From the nytimes.com
More examples
Emotionlessness: apathy demonstrated by an absence of emotional reactions
Apathy (also called impassivity or perfunctoriness) is a state of indifference, or the suppression of emotions such as concern, excitement, motivation and passion. An apathetic individual has an absence of interest in or concern about emotional, social, or physical life. ...