Meaning & use
deadly
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Meanings
adjectivecomparable
Able to kill or likely to cause death.
Grammar: Comes before a noun or after a verb: a deadly snake, the poison is deadly.
Patterns
- deadly to someone
The cobra's venom is deadly to humans.
Deadly fumes filled the closed garage.
The storm was the deadliest in a decade.
adjectivebefore a nounfigurative
Extremely harmful or damaging, even if not physically fatal.
Grammar: Often figurative: a deadly mistake, a deadly blow.
One deadly error cost the team the match.
Gossip can be deadly to a friendship.
The review dealt a deadly blow to the film's chances.
adjectivebefore a nouninformal
Used to emphasize how serious, dull or exact something is.
Grammar: Informal intensifier in phrases like deadly serious or deadly dull.
Patterns
- deadly serious
- deadly dull
He was deadly serious about quitting.
The lecture was deadly dull and went on for hours.
She took aim with deadly precision.
adverbnot comparableinformalBritish
Extremely; used for emphasis before an adjective.
Grammar: Informal, mainly British and Irish: deadly boring.
Patterns
- deadly boring
The party was deadly boring.
I'm deadly serious about this.
It was a deadly quiet street at that hour.
Word forms
| comparative | deadlier |
|---|---|
| superlative | deadliest |
Common combinations
- deadly weapon
- He was charged with carrying a deadly weapon.
- deadly disease
- Malaria remains a deadly disease in many regions.
- deadly force
- Officers may use deadly force only in extreme cases.
- deadly serious
- I'm deadly serious about moving abroad.
- deadly silence
- A deadly silence followed his announcement.
- deadly sins
- Pride is one of the seven deadly sins.
Synonyms and how they differ
- lethal
- Lethal is a little more technical and used for doses, weapons and substances, while deadly is more general.
- fatal
- Fatal describes something that actually caused death, whereas deadly describes something capable of it.
- dangerous
- Dangerous means risky, but not always likely to kill, so it is milder than deadly.
- mortal
- Mortal is more formal and literary, and used in phrases like a mortal wound.
Opposites
Word family
Commonly confused: deadly or deathly? deadly or dead?
deadly vs deathly
Deathly means like death, as in a deathly pale face, while deadly means capable of causing death.
deadly vs dead
Dead means no longer alive; deadly describes what can cause that.
Practice
The mushroom looks harmless, but it is ____ if eaten.
Choose one answer.
Deadly means capable of causing death. Deathly describes appearance or feeling, dead means already not alive, and deadened means made less sharp.
Make it your own
Write a sentence using “deadly”, then check it and compare it with the examples above.