Imperturbable suggests deep calmness, implying someone doesn't let emotions control them. His imperturbable nature during the crisis reassured everyone.
Pro Tip 2/3
Not Indifference
Imperturbable isn't the same as not caring; it shows calmness despite caring deeply. She was imperturbable while awaiting the verdict but cared greatly about the outcome.
Pro Tip 3/3
Positive Connotation
Imperturbable usually has a positive sense, admired as strength or confidence in tough situations. The imperturbable leader navigated the negotiations successfully.