Stoical
Etymology
From the ancient Greek philosophical school of the Stoics, who taught that virtue and reason should keep one serene amid pain, loss, and misfortune. The school was named for the Stoa Poikile, the "painted porch" in Athens where its founder Zeno taught. Over centuries "stoical" drifted from the specific philosophy to the general trait of bearing adversity without visible distress.
adjective · /STOH-ih-kul/
Enduring hardship or pain calmly and without complaint.
What it names
The unflinching composure of a person who takes bad news or real suffering with a steady, uncomplaining face.
Example
She remained stoical through the diagnosis, asking practical questions in a level voice.
Related idea
Impassive means showing no emotion at all; stoical implies real feeling deliberately mastered, endurance rather than mere blankness.