[英和辞典] （苦しみ・喜びなどに）無関心な人，克己心の強い人；禁欲（克己）主義者
[英英辞典] stoic: indifferent to or unaffected by pleasure or pain; also, one who is stoic.(Dictionary.com)
[例文]
AP - After the Portland Trail Blazers won their 11th straight game, normally stoic owner Paul Allen looked directly at a camera and jubilantly held up one finger on each hand to signify the streak.