aequanimus
From LSJ
ὡς οὐ δικαίως θάνατον ἔχθουσιν βροτοί, ὅσπερ μέγιστον ῥῦμα τῶν πολλῶν κακῶν → since unjustly men hate death, which is the greatest defence against their many ills
Latin > English (Lewis & Short)
aequănĭmus: a, um aequus-animus, adj.,
I even-tempered, patient, composed, calm: aequanimus fiam, Aus. Sept. Sap. 3: nulla fuit res parva umquam aequanimis, id. Idyll. 3, 9>