Definition of deadly in English:

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Pronunciation: /ˈdedlē/

adjective (deadlier, deadliest)

1Causing or able to cause death: a deadly weapon
More example sentences
  • It is also important to remember that every driver on the highway is armed with a weapon more deadly and dangerous than any firearm: a motor vehicle.
  • The 2003 death toll from the deadly virus was only one.
  • In Doomsday Book the twenty-first century is stricken by yet another pandemic, almost as deadly as the Black Death was in the fourteenth.
fatal, lethal, mortal, death-dealing, life-threatening;
dangerous, injurious, harmful, detrimental, deleterious, unhealthy;
literary deathly
1.1Filled with hate: his voice was cold and deadly
More example sentences
  • Their hate campaign is paying deadly dividends.
  • An unearthly calm seemed to come over him then, and there was a feeling of deadly malice, of hate and violence radiating from him that made her flinch from his stare.
  • Voice hated Azrael with a deadly passion.
mortal, irreconcilable, implacable, unappeasable, unforgiving, remorseless, merciless, pitiless;
bitter, hostile, antagonistic
1.2(Typically in the context of shooting or sports) extremely accurate, effective, or skillful: his aim is deadly
More example sentences
  • Practice this in front of a mirror until you can slightly part your lips and silently hit a target with deadly accuracy.
  • Each strike and block was performed with flawless, deadly accuracy.
  • Hinting at the timepiece's capacity for deadly accuracy, he adds: ‘It was twenty-four minutes past midnight.’
unerring, unfailing, impeccable, perfect, flawless, faultless;
sure, true, precise, accurate, exact, bang on
1.3 informal Extremely boring: he’s well meaning, but so utterly deadly
More example sentences
  • Viewers today typically consider busts academic, boring, deadly; in a museum, they are what you walk past on the way to the Impressionists.
  • As a result, cultural choice is increasingly restricted, and a bland sameness, deadly and soporific, threatens the cultural landscape.
  • I barely even notice the battle anymore through the deadly monotony.
1.4 [attributive] Complete; total: she was in deadly earnest
More example sentences
  • Morgan Freeman was now speaking in deadly earnest about Rainforests as the Lungs of Our Planet.
  • Byron may have been playing at soldiers, but at the same time he was in deadly earnest.
  • There are things of deadly earnest that can only be mentioned under the cover of a joke.
intense, great, marked, extreme
in every way, one hundred percent, to the hilt


[as submodifier]
1In a way resembling or suggesting death; as if dead: her skin was deadly pale
More example sentences
  • All the while being deadly silent, since I live with my grandmother and her bedroom is right next to the bathroom.
  • The party mood was gone and everyone was deadly quiet.
  • His face was deadly white, a bloody bandage swathed his neck, and his rainproof was soaked with the blood of a sniper's victim.
1.1Extremely: a deadly serious remark
More example sentences
  • This joking remark caused Eisenhower to turn deadly serious.
  • Elves are that way though, jolly one moment and deadly serious when the situation needs it.
  • Heart failure is a deadly serious condition, but with good treatments people can double or triple their life expectancy.



Pronunciation: /ˈdedlēnəs/
Example sentences
  • The bomb was packed with shards of metal, nuts and bolts to increase its deadliness.
  • By contrast, the deadliness of contaminants added to reservoirs or water sources would most likely be neutralized by dilution and standard water treatment.
  • No one with any sense would place a trap of such deadliness so close to a populated area.


Old English dēadlīc 'mortal, in danger of death' (see dead, -ly1).

Words that rhyme with deadly

Hedley, medley, redly
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