Impassibleness is a state of emotional detachment or apathy. Synonyms for this word include stoicism, indifference, dispassion, impassivity, calmness, and coolness. These words describe a lack of emotion or the ability to remain unaffected by external factors. Stoicism emphasizes enduring pain and hardship without complaint, while indifference implies a lack of caring or concern. Dispassion refers to a total absence of emotion or bias, while impassivity describes a lack of visible emotion or expression. Calmness and coolness imply a state of inner peace or composure regardless of the situation. All of these synonyms share the common trait of emotional detachment or a reserved demeanor.