DISPLAYED DISPLEASURE can be expressed in a variety of ways, such as hissing, booing, and hooting. Hissing is a sound made by forcing air through the teeth, usually to express disapproval or displeasure. Booing is a loud, harsh sound made to show disapproval or contempt. Hooting is a loud, prolonged sound made to express disapproval or derision. All three of these expressions are used to display displeasure in a public setting.