Perspire/pərˈspaɪər/ Definition 1 of 2Pro Tip 1/3Physical Reaction Perspire describes a natural body response, it's not a choice. Even in the shade, he began to perspire during the workout. Pro Tip 2/3Heat and Stress Primarily used when discussing heat or anxiety-induced sweating. Interviews always make me nervous and perspire. Pro Tip 3/3Formality Level More formal and less commonly used than 'sweat'. He preferred to say 'perspire' rather than 'sweat' in the meeting.