boo

US /buː/
UK /buː/
1.

hú hú

said suddenly to surprise someone who is unaware of one's presence.

:
‘Boo!’ she cried, jumping up to frighten him
2.

hú hú

said to show disapproval or contempt.

:
‘There's only one bar.’ ‘Boo!’
1.

hú hú

an utterance of ‘boo’ to show disapproval of a speaker or performer.

:
the audience greeted this comment with boos and hisses
1.

hú hú

say ‘boo’ to show disapproval of a speaker or performer.

:
they booed and hissed when he stepped on stage