The term 'sound of disgust' can be expressed in a variety of ways, including 'booing' (6 letters), 'ptui' (4 letters), 'UGH' (3 letters), 'SNORT' (5 letters), 'pah' (3 letters), and 'phew' (4 letters). Booing is a sound made by a group of people to express disapproval or dissatisfaction. Ptui is an expression of disgust or contempt, often accompanied by a spitting sound. UGH is an expression of disgust or annoyance. SNORT is a sound made through the nose to express contempt, derision, or disbelief. Pah is an expression of contempt or disgust. Finally, phew is an expression of relief or satisfaction.