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Synonyms

deadly

American  
[ded-lee] / ˈdɛd li /

adjective

deadlier, deadliest
  1. causing or tending to cause death; fatal; lethal.

    a deadly poison.

  2. aiming to kill or destroy; implacable.

    a deadly enemy.

  3. like death.

    a deadly pallor.

  4. excruciatingly boring.

    The dinner party was absolutely deadly.

    Synonyms:
    dreary, tedious, dull
  5. excessive; inordinate.

    deadly haste.

  6. extremely accurate.

    Annie Oakley was a deadly shot.


adverb

  1. in a manner resembling or suggesting death.

    deadly pale.

  2. excessively; completely.

    deadly dull.

deadly British  
/ ˈdɛdlɪ /

adjective

  1. likely to cause death

    deadly poison

    deadly combat

  2. informal extremely boring

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adverb

  1. like death in appearance or certainty

    deadly pale

    a deadly sleep

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Related Words

See fatal.

Other Word Forms

  • deadliness noun
  • nondeadly adjective

Etymology

Origin of deadly

First recorded before 900; Middle English deedli(ch), Old English dēadlīce; dead, -ly

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

His predecessor, Ayatollah Ruhollah Khomeini, had left the nation bankrupt and humiliated, following an eight-year war with neighboring Iraq, one of the deadliest global conflicts of the past century.

From The Wall Street Journal

Airlines serving the Middle East have cancelled or diverted flights after the US and Israel launched deadly strikes on Iran.

From BBC

And after resolving a plagiarism dispute that delayed its release last year, the French-language thriller “The Hunt,” about a deadly encounter between two groups of hunters, is finally landing on March 4.

From MarketWatch

And leading AI systems are not yet reliable to be trusted to power deadly weapons without a human in ultimate control, he added.

From Barron's

Afghan forces attacked Pakistani border troops on Thursday night in what the Taliban government said was retaliation for earlier deadly air strikes, while AFP journalists in Kabul and Kandahar heard blasts and jets overhead.

From Barron's