unruffled, impassive, expressionless
Rudolph avait dit ça d’un ton parfaitement impassible.
Rudolph had said it in a perfectly deadpan tone.
La porte s'ouvrit, et l'impassible gentleman parut.
The door opened, and the impassive gentleman appeared.
L'impassible Fogg attendait sans manifester ses sentiments.
The impassive Fogg waited without showing his feelings.
She remained impassive.
Quoi que vous entendiez ou voyiez, restez impassible.
No matter what you hear or see, remain calm.