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deadly

/ˈded.li/
IELTSAcademic
adjective

Causing death, or very likely to cause death. It can also mean extremely dangerous or severe.

  • He suffered a deadly wound.
  • The snake has a deadly bite.
  • A deadly disease spread quickly.
adverb

Used informally to mean very or extremely. It is common in speech, not formal writing.

  • That was deadly funny.
  • She looked deadly serious.
  • The exam was deadly hard.

Adinary Nuance

Deadly is stronger than dangerous or harmful. It suggests real risk of death, or something so intense it feels severe. For informal speech, it can also mean 'very', but this use is less suitable in formal writing. Writers often choose deadly when they want a stronger, sharper effect than serious or severe.

In other languages

Vietnamese
chết người
Spanish
mortal
Chinese
致命的
Japanese
致命的な
Korean
치명적인

Etymology

Deadly comes from Old English deadlic, from dead and the suffix -ly, meaning 'having the nature of death'. In English, it later also gained the informal sense 'extremely'.

Common phrases

deadly weapondeadly diseasedeadly seriousdeadly force

Synonyms

Related words

Frequently asked questions

Is deadly the same as dangerous?
Not exactly. Deadly is stronger and usually means something can cause death.
Can deadly be used informally?
Yes. In speech, deadly can mean 'very' or 'extremely', especially in some varieties of English.
Is deadly formal or informal?
The adjective is neutral and often formal. The adverb use is informal.
What is the difference between deadly and fatal?
Fatal usually describes the result. Deadly often describes the thing that can cause death.