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 and vegetables) onstage, though the objects may not be meant to physically hurt the performer.
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. Some baseball players who have been booed have stated that booing "spooked" or "bothered" them or their teammates, and that it "affected their performance". Another player stated concerning booing, "It hurts" and another stated, "It frustrates me when the crowd boos".