lethal
1 of 2adjective
le·thal ˈlē-thəl 
1
a
: of, relating to, or causing death
death by lethal injection
b
: capable of causing death
lethal chemicals
2
: gravely damaging or destructive : devastating
a lethal attack on his reputation
3
: very potent or effective
a lethal fastball
also : having a high alcohol content
a lethal rum punch
lethality
lē-ˈtha-lə-tē
noun lethally
ˈlē-thə-lē
adverb lethal
2 of 2noun
1
: an abnormality of genetic origin causing the death of the organism possessing it
2
: lethal gene
Synonyms
Adjective
- baleful
- deadly
- deathly
- fatal
- fell
- killer
- mortal
- murderous
- pestilent
- terminal
- vital
See all Synonyms & Antonyms 
Example Sentences
Adjective a potentially lethal dose of a drug He was sentenced to death by lethal injection.
Recent Examples on the Web
Ike Morgan | Imorgan@al.com, al, 13 Sep. 2022 State lawmakers voted in spring 2021 to authorize death by firing squad and electrocution when lethal injection is not an option. Derek Hawkins, Washington Post, 7 Sep. 2022 South Carolina, which conducted its last execution in 2011, is one of several states that have been unable to procure the drugs necessary for lethal injection, which many states have seen as the most humane form of execution. Daniel Victor, New York Times, 7 Sep. 2022 South Carolina, which conducted its last execution in 2011, is one of several states that have been unable to procure the drugs necessary for lethal injection, which many states have seen as the most humane form of execution. Daniel Victor, BostonGlobe.com, 7 Sep. 2022 Just three prisoners in South Carolina have chosen the electric chair since lethal injection was made available in 1995. Kathryn Casteel, USA TODAY, 6 Sep. 2022 The last one took place in 2019, when a lethal injection was administered to Gary Ray Bowles, known as the I-95 killer for his 1994 murders of six gay men in North Florida. David Fleshler, Sun Sentinel, 3 Sep. 2022 Alabama does not allow witnesses from news outlets to watch the preparations for a lethal injection. Kim Chandler, BostonGlobe.com, 30 Aug. 2022 He was executed by lethal injection on July 28, 2022, near Atmore, Alabama. CBS News, 30 Aug. 2022 Washington Post, 4 Sep. 2020 In response to Russian operations and Chinese advances, the USAF is battling for air superiority in the Arctic with its most valuable—and lethal—assets in Alaska, including the F-22A Raptor and F-35A Joint Strike Fighter. Jeff Bolton, Popular Mechanics, 19 July 2020 See More
Adjective
Could nitrogen hypoxia be used in place of lethal injection for Alabama’s next execution? Ike Morgan | Imorgan@al.com, al, 13 Sep. 2022 State lawmakers voted in spring 2021 to authorize death by firing squad and electrocution when lethal injection is not an option. Derek Hawkins, Washington Post, 7 Sep. 2022 South Carolina, which conducted its last execution in 2011, is one of several states that have been unable to procure the drugs necessary for lethal injection, which many states have seen as the most humane form of execution. Daniel Victor, New York Times, 7 Sep. 2022 South Carolina, which conducted its last execution in 2011, is one of several states that have been unable to procure the drugs necessary for lethal injection, which many states have seen as the most humane form of execution. Daniel Victor, BostonGlobe.com, 7 Sep. 2022 Just three prisoners in South Carolina have chosen the electric chair since lethal injection was made available in 1995. Kathryn Casteel, USA TODAY, 6 Sep. 2022 The last one took place in 2019, when a lethal injection was administered to Gary Ray Bowles, known as the I-95 killer for his 1994 murders of six gay men in North Florida. David Fleshler, Sun Sentinel, 3 Sep. 2022 Alabama does not allow witnesses from news outlets to watch the preparations for a lethal injection. Kim Chandler, BostonGlobe.com, 30 Aug. 2022 He was executed by lethal injection on July 28, 2022, near Atmore, Alabama. CBS News, 30 Aug. 2022 Noun
Almost 8 of 10 lethal overdose victims had no contact with the agency before their deaths, the report found. Washington Post, 4 Sep. 2020 In response to Russian operations and Chinese advances, the USAF is battling for air superiority in the Arctic with its most valuable—and lethal—assets in Alaska, including the F-22A Raptor and F-35A Joint Strike Fighter. Jeff Bolton, Popular Mechanics, 19 July 2020 See More Word History
Etymology
Adjective and Noun
Latin letalis, lethalis, from letum death
First Known Use
Adjective
circa 1604, in the meaning defined at sense 1a
Noun
1917, in the meaning defined at sense 1
Phrases Containing lethal
Medical Definition
lethal 1 of 2
adjective
le·thal ˈlē-thəl
: of, relating to, or causing death
a lethal injury
also : capable of causing death
lethal chemicals
a lethal dose
lethal
2 of 2noun
1
: an abnormality of genetic origin causing the death of the organism possessing it usually before maturity
2
: lethal gene
lethal
adjective
as in deadly
likely to cause or capable of causing death we were lucky that the snake's venom wasn't lethal, and our friend turned out to be all right Synonyms & Similar Words
Relevance
- deadly
- fatal
- poisonous
- infectious
- infective
- harmful
- killer
- toxic
- dangerous
- terminal
- murderous
- destructive
- fell
- mortal
- hazardous
- deathly
- injurious
- deleterious
- pernicious
- vital
- virulent
- baleful
- pestilent
- risky
- noxious
- serious
- perilous
- threatening
- baneful
- menacing
- sublethal
- ugly
- bloody
- pestilential
- unhealthy
- jeopardizing
- truculent
- grave
- sanguinary
- grievous
- parlous
- unsound
- sanguine
- internecine
Antonyms & Near Antonyms
- nonlethal
- beneficial
- healthy
- nonfatal
- healthful
- wholesome
- beneficial
- curative
- salutary
- salubrious
- restorative
- useful
- corrective
- remedial
- advantageous
- tonic
- nontoxic
- safe
- alleviative
- nonpoisonous
Synonym Chooser
Some common synonyms of lethal are deadly, fatal, and mortal. While all these words mean "causing or capable of causing death," lethal applies to something that is bound to cause death or exists for the destruction of life.
lethal gas
The words deadly and lethal can be used in similar contexts, but deadly applies to an established or very likely cause of death.
a deadly disease
Although the words fatal and lethal have much in common, fatal stresses the inevitability of what has in fact resulted in death or destruction.
fatal consequences
While in some cases nearly identical to lethal, mortal implies that death has occurred or is inevitable.
a mortal wound
- keeping company (with)
- keeping company with
- keeping company with the likes of
- keeping down
- keeping from
- keeping going
- keeping in
- keeping off
- keeping on
- keeping one's eyes open
- keeping one's eyes open (for)
- keeping one's eyes open for
- keeping out
- keeping posted
- keeping room
- keeping someone posted
- keeping to
- keeping up
- keeping up (with)
- keeping up with
- keepings
- keepnets
- keeps
- keeps (back)
- keeps (from)