I. ˈbü interjection
Etymology: Middle English bo
Date: 15th century
— used to express contempt or disapproval or to startle or frighten
II. noun
( plural boos )
Date: 1801
1. : a shout of disapproval or contempt
2. : any utterance at all — usually used in negative constructions
never said boo
III. verb
Date: 1884
intransitive verb
: to deride especially by uttering a prolonged boo
transitive verb
: to express disapproval of by booing
the crowd boo ed the referee