Definition of "equanimity"

No doubt you are right, my best of friends, there would be far less suffering amongst mankind, if men—and God knows why they are so fashioned—did not employ their imaginations so assiduously in recalling the memory of past sorrow, instead of bearing their present lot with equanimity.

1779, Johann Wolfgang von Goethe, The Sorrows of Young Werther

Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment.

1954, Albert Einstein, Ideas and Opinions

We find Hudson himself, a vision of unwavering equanimity, admitting that as a child he didn’t dare mention his acting dreams for fear they would be dismissed as “sissy stuff”.

2023 October 6, Ryan Gilbey, “The double life of Rock Hudson: ‘Let’s be frank, he was a horndog!’”, in The Guardian‎