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adverb

Synonym Chooser

How does the adjective deadly differ from other similar words?

Some common synonyms of deadly are fatal, lethal, and mortal. While all these words mean "causing or capable of causing death," deadly applies to an established or very likely cause of death.

a deadly disease

When would fatal be a good substitute for deadly?

In some situations, the words fatal and deadly are roughly equivalent. However, fatal stresses the inevitability of what has in fact resulted in death or destruction.

fatal consequences

When is lethal a more appropriate choice than deadly?

While in some cases nearly identical to deadly, lethal applies to something that is bound to cause death or exists for the destruction of life.

lethal gas

When could mortal be used to replace deadly?

The synonyms mortal and deadly are sometimes interchangeable, but mortal implies that death has occurred or is inevitable.

a mortal wound

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of deadly
Adjective
While there were no immediate reports of damage or injuries, the area is still recovering from a large, deadly earthquake that struck last week. Hollie Silverman, MSNBC Newsweek, 14 Oct. 2025 Most were detainees taken by Israeli forces during the war in Gaza; however, the group also included 250 prisoners convicted of involvement in deadly attacks or held under suspicion of such security offenses, according to Reuters. Kathryn Palmer, USA Today, 13 Oct. 2025
Adverb
Max Esmail While the designer is quick to crack a joke, his collection is deadly serious. Jean E. Palmieri, Footwear News, 12 Sep. 2025 This plot was carefully crafted and deadly serious. Meredith Kile, People.com, 11 Sep. 2025 See All Example Sentences for deadly
Recent Examples of Synonyms for deadly
Adjective
  • McIlroy’s driver is typically his most lethal weapon.
    Devlina Sarkar, MSNBC Newsweek, 17 Oct. 2025
  • Less than a month later, Skaggs died alone in a hotel room in Southlake, Texas, at the beginning of an Angels road trip of what was later determined to be a lethal combination of fentanyl, oxycodone and alcohol.
    Sean Emery, Oc Register, 16 Oct. 2025
Adjective
  • Or does the sheer scale of the challenge demand the capacity, availability and rock-bottom prices that only established Chinese suppliers can provide?
    Andrew Saunders, Fortune, 15 Oct. 2025
  • While the bans would have only applied in California, the state’s sheer size gives it significant influence over what gets manufactured for sale across the nation.
    Rachel Frazin, The Hill, 14 Oct. 2025
Adjective
  • Mind or spirit is mortal and physical and thus cannot exist without the body.
    Literary Hub, Literary Hub, 10 Oct. 2025
  • The Patriots weren’t much cleaner, with eight penalties, but a combination of errors made a Bills offense that had scored 30-plus in every game — the only NFL team to do that this season — look mortal.
    Andrew Greif, NBC news, 6 Oct. 2025
Adverb
  • The last six decades or so have been an extremely subtle hint, and the rest of us have cracked the code.
    Sean McIndoe, New York Times, 17 Oct. 2025
  • In extremely dense fog where visibility is near zero, the best course of action is to first turn on your hazard lights, then simply pull into a safe location such as a parking lot of a local business, and stop.
    CA Weather Bot, Sacbee.com, 17 Oct. 2025
Adjective
  • The illness is rarely fatal, and most patients recover within a week, though some may experience persistent joint pain, authorities continued.
    Jon Haworth, ABC News, 15 Oct. 2025
  • Early intervention While uterine cancer can be fatal, an early diagnosis means potentially faster treatment and better outcomes.
    Khloe Quill, FOXNews.com, 15 Oct. 2025
Adjective
  • Cambodia and Thailand agreed to an unconditional ceasefire after talks in Malaysia on July 28.
    Colin Meyn, The Hill, 9 Oct. 2025
  • Yet Make Me Commissioner is anything but an unconditional love letter to the game.
    Mark Leibovich, The Atlantic, 8 Oct. 2025
Adjective
  • Within the first 20 minutes of the sixth and penultimate episode of Task, both PSP Lizzie Stover (Alison Oliver) and Robbie Prendergrast (Tom Pelphrey) are dead.
    Megan McCluskey, Time, 13 Oct. 2025
  • Four people were found dead at the scene, and at least 20 other people were injured.
    NPR, NPR, 13 Oct. 2025
Adverb
  • With someone like Charles, whose world is incredibly high-pressure and constantly moving — and a big thing is trust.
    Kanika Talwar, Footwear News, 16 Oct. 2025
  • But playing shortstop in the big leagues at an elite level is incredibly difficult.
    Jim Alexander, Oc Register, 16 Oct. 2025

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Cite this Entry

“Deadly.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/deadly. Accessed 18 Oct. 2025.

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