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PlainSpell

boo

/buː/interjection, noun, verb

boo is spelled B-O-O: 3 letters and one syllable. It appears 8.3 times per million words in written English, the 8,036th most frequent word form (wordfreq, 2021 data). As an interjection, boo means “A loud exclamation intended to scare someone. Usually used when one has been hidden from the target, and then appears unexpectedly” (English Wiktionary, September 2026).

How many letters and syllables are in boo?

Letters3: B-O-O
Syllables1 (from its American pronunciation)
In writing8.3 times per million words; the 8,036th most frequent word form
Wrong spellings searchednone measured in search

Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

How common is boo?

Boo appears 8.3 times per million words in written English, the 8,036th most frequent word form in the list.

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

How do you pronounce boo?

  • /buː/

Boo has one syllable (counted from its American pronunciation in the CMU Pronouncing Dictionary).

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-au-boo.ogg, En-us-boo.ogg, En-us-boo2.ogg, Wikimedia Commons (author and licence on each file's page).

Forms of boo

  • boos plural, present, singular, he/she/it
  • booing participle, present
  • booed participle, past

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What does boo mean?

The meanings the English Wiktionary records, quoted as written there (source below).

interjection

  1. 1

    A loud exclamation intended to scare someone. Usually used when one has been hidden from the target, and then appears unexpectedly.

  2. 2

    An exclamation used by a member of an audience, as at a stage play or sporting event, to indicate derision or disapproval.

noun

  1. 1

    A derisive shout of the word 'boo' made to indicate disapproval.

  2. 2

    CanadaUSslangA close acquaintance or significant other.

  3. 3

    slangCannabis.

  4. 4

    A tail feather from an ostrich.

verb

  1. 1

    To shout extended boos derisively.

    When he took the podium, the crowd booed.

  2. 2

    To shout extended boos at, as a form of disapproval or derision.

    The protesters loudly booed the visiting senator.

  3. 3

    archaicTo make a sound characteristic of cattle; to moo.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

Boo in Spanish, French, German and Portuguese

LanguageWords
Frenchbouh, hou (loud exclamation intended to scare someone), huer (to shout boos derisively (intransitive))
Germanbuh (loud exclamation intended to scare someone), buhen (to shout boos derisively (intransitive)), Buhruf (derisive shout), ausbuhen (to shout boos at (transitive))
Portuguesebu (loud exclamation intended to scare someone), vaiar, apupar (to shout boos derisively (intransitive)), vaia, apupo (derisive shout)
Spanishbu (loud exclamation intended to scare someone), abuchear (to shout boos derisively (intransitive)), abucheo, befa (derisive shout), uuh (word used ironically in a situation where one…)

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.

Where does boo come from?

From earlier (15c.) boh, coined to create a loud and startling sound. Compare Middle English bus! (“bang!”, interjection), Latin boō (“cry aloud, roar, shout”, verb), Ancient Greek βοάω (boáō, “shout”, verb).

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What to look up after boo