What is the root word of equanimity?

The root word of "equanimity" is "equ", which is derived from the Latin word "aequus", meaning "equal" or "level".

"Equanimity" itself means a state of mental calmness, composure, and evenness of temper, especially in a difficult situation. It is essentially the state of being "equal" in your emotions and reactions, regardless of external circumstances.