Answer
Cool Jazz is the genre most closely associated with Toots Thielemans' style. This genre emerged in the 1940s and 1950s as a reaction to the intensity and complexity of bebop. Cool Jazz is characterized by a more relaxed and melodic approach, with a focus on improvisation and a subdued emotional expression. Thielemans' playing embodied these qualities, with his signature harmonica and guitar work showcasing his melodicism and improvisational skills.