Phrase guide

loose cannon

noun · verb · 4 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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  • Australia: Recorded audio is listed in the source snapshot.

1

noun

Meaning 1

A cannon that breaks loose from its moorings on a ship during battle or storm, with the potential to cause serious damage to the ship and her crew.

Definition source: English Wiktionary via Wiktextract

Topics: nautical, transport

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

An uncontrolled or unpredictable person, especially considered liable to cause unintentional or indiscriminate damage.

Definition source: English Wiktionary via Wiktextract

Usage: broadly, idiomatic

Examples

  • Jack is considered a loose cannon due to his volatile personality and his track record of being unable to maintain his composure.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

verb

Meaning 3

To behave in a way such as to cause unintentional or indiscriminate damage.

Definition source: English Wiktionary via Wiktextract

Usage: idiomatic, intransitive

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

4

noun

Meaning 4

a person who is expected to perform a particular task but who is out of control and dangerous

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: person, individual, someone, somebody, mortal, soul

History

Etymology

No etymology was provided for this word.

Across languages

Translations

15 source translations are retained for this English entry.

  • Chinese Mandarin: 脱缰野马 — unpredictable person
  • Czech: neřízená střela — unpredictable person
  • Dutch: ongeleid projectiel — unpredictable person
  • Estonian: ennustamatu käitumisega inimene — unpredictable person
  • Finnish: kävelevä katastrofi — unpredictable person
  • Finnish: arvaamaton ihminen — unpredictable person
  • French: électron libre — unpredictable person
  • German: unberechenbarer Mensch — unpredictable person
  • German: unkontrollierbarer Mensch — unpredictable person
  • German: gemeingefährlicher Mensch — unpredictable person
  • Hungarian: elszabadult hajóágyú — unpredictable person
  • Italian: mina vagante — unpredictable person
  • Russian: обезья́на с грана́той f /lit: monkey with a grenade/ (obezʹjána s granátoj) — unpredictable person
  • Spanish: bala perdida — unpredictable person
  • Turkish: serseri mayın — unpredictable person