deadly
[adjective]
Synonyms:
- lethal, dangerous, death-dealing, deathly, fatal, malignant, mortal
- boring, dull, mind-numbing, monotonous, tedious, tiresome, uninteresting, wearisome

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Contrasted words: healthful, healthy, wholesome, advantageous, beneficial, restorative, sanative, harmless, innocuous, inoffensive, unoffending
Related Words: destroying, destructive, killing, slaying, internecine, baneful, noxious, pernicious, poisonous, toxic, virulent

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English Thesaurus: poisonous, toxic, noxious, hazardous, deadly, ...

[TahlilGaran] English Synonym Dictionary ▲

I. dead‧ly¹ /ˈdedli/ adjective
[Word Family: noun: dead, death, deadliness; adjective: dead, deadly, deathly; adverb: deadly, deathly; verb: deaden]

1. VERY DANGEROUS likely to cause death Synonym : lethal:
a deadly poison
a deadly weapon
deadly disease/virus

2. deadly enemy someone who will always be your enemy and will try to harm you as much as possible:
The two rapidly became deadly enemies.

3. COMPLETE complete or total:
We sat in deadly silence.
He was in deadly earnest (=completely serious).

4. VERY EFFECTIVE causing harm in a very effective way:
She hit the target with deadly accuracy.

5. LIKE DEATH [only before noun] like death in appearance:
His face had a deadly paleness.
⇒ seven deadly sins at sin¹(1)

[TahlilGaran] Dictionary of Contemporary English ▲

II. deadly² adverb
[Word Family: noun: dead, death, deadliness; adjective: dead, deadly, deathly; adverb: deadly, deathly; verb: deaden]
deadly serious/dull/boring etc very serious, dull etc:
I’m deadly serious, this isn’t a game!

[TahlilGaran] Dictionary of Contemporary English ▲

poisonous containing or producing a substance that is likely to kill you, or make you very ill:
poisonous gas
poisonous snakes
The plant is poisonous to humans and animals.
toxic toxic chemicals and waste are poisonous to people and the environment:
Crops were sprayed with highly toxic chemicals.
Lead is toxic to humans.
The site was used for the disposal of toxic waste.
noxious [usually before noun] formal noxious substances and gases are poisonous:
Vehicles pollute the air with noxious fumes
The soil may be contaminated with noxious substances.
hazardous [usually before noun] hazardous substances are likely to harm people, animals, or the environment if they are not dealt with or got rid of carefully:
Lead is one of the most hazardous substances known, causing cancer and nerve damage.
The building is now unoccupied, and all radioactive or hazardous materials have been removed.
hazardous nuclear waste
deadly extremely poisonous and likely to kill you – used especially about poisons and snakes:
a deadly poison
a deadly snake
Terrorists plotted to release a deadly gas.

[TahlilGaran] English Thesaurus ▲