Booing is an act of showing displeasure for someone or something, generally an entertainer, by loudly yelling boo! (and holding the "oo" sound) or making other noises of disparagement, such as hissing. People may make hand signs at the entertainer, such as the thumbs down sign. If spectators particularly dislike the performance they may also accompany booing by throwing objects (traditionally rotten fruit) onstage, though the objects may not be meant to physically hurt the performer.
Booing performers has a very long history, The first written record comes from ancient Greece. At the annual Festival of Dionysia in Athens, playwrights competed to determine whose tragedy was the best. When the democratic reformer Cleisthenes came to power in the 6th century B.C., audience participation came to be regarded as a civic duty. The audience applauded to show its approval and shouted and whistled to show displeasure. In ancient Rome, jeering was common at the gladiatorial games, where audience participation often determined whether a competitor lived or died.
While people have expressed displeasure publicly since ancient times, the English word boo was first used in the early 19th century to describe the lowing sound that cattle make. Later in the 19th century, the word came to be used to describe the disapproving cry of crowds. Hoot, another onomatopoeic English word, was used as early as 1225 to describe the same phenomenon. (Ancient Greek and Latin both contain words resembling boo that mean "to cry or shout aloud," though there is no known etymological connection to the modern English word.)This practice has in recent times come under criticism. The opinion is often expressed that to boo a bad performance is unkind and demonstrates a lack of sophistication. However, the counterargument goes that the combination of booing and applause help keep the quality of public performance high, by emotionally rewarding the good and punishing the bad.