killer
1 of 2noun
kill·er ˈki-lər 
1
: one that kills
2
: killer whale
3
a
: one that has a forceful, violent, or striking impact
b
: one that is extremely difficult to deal with
killer
2 of 2adjective
1
: strikingly impressive or effective
a killer smile
a killer résumé
2
: extremely difficult to deal with
a killer fastball
also : causing death or devastation
a killer tornado
Synonyms
Noun
- bear
- beast
- chore
- headache
- job
- labor
Adjective
- baleful
- deadly
- deathly
- fatal
- fell
- lethal
- mortal
- murderous
- pestilent
- terminal
- vital
See all Synonyms & Antonyms 
Example Sentences
Noun Heart disease is the leading killer of both men and women. The chemical is used as a weed killer. Adjective killer viruses that claimed millions of lives a killer exercise program guaranteed to whip you into shape
Recent Examples on the Web
Manori Ravindran, Variety, 1 Sep. 2022 And now, finally, Krystal's mother, my friend Josephine Wentzel, who has spent these past years tracking down her daughter's killer, may have a peaceful night's sleep. Michael Ruiz, Fox News, 30 Aug. 2022 Gandy’s grandmother, Karen Parson, said the family just wants to see justice for her, meaning an arrest and a conviction of Gandy’s killer. Desiree Stennett, Orlando Sentinel, 30 Aug. 2022 Other notes provided insight into the killer's mindset. Chris Harris, Peoplemag, 10 Aug. 2022 Gary Ramirez was linked to the 1982 killing of Karen Stitt, 15, after a Sunnyvale police detective was alerted to the killer's possible identity last year, according to court documents filed in Santa Clara County. Tim Stelloh, NBC News, 10 Aug. 2022 Flitting through realities, Kirby and Dan race to end the killer's reign of terror in a series that masterfully blends together sci-fi, horror, and feminist drama. Jace Lacob, EW.com, 25 July 2022 Investigators performed a handwriting comparison to confirm the notes were written by Gabe’s ex-boyfriend and alleged killer, 27-year-old Marshall Curtis Jones, according to CBS News. Susie Neilson, San Francisco Chronicle, 9 July 2022 Some survived the Colorado hammer killer's barbaric attacks. Kc Baker, PEOPLE.com, 6 July 2022 See More
Noun
Plus, there’s a killer ensemble that includes Anya Taylor-Joy, Nicholas Hoult, Hong Chau and Janet McTeer, which should be enough to whet the appetite of film fans. Manori Ravindran, Variety, 1 Sep. 2022 And now, finally, Krystal's mother, my friend Josephine Wentzel, who has spent these past years tracking down her daughter's killer, may have a peaceful night's sleep. Michael Ruiz, Fox News, 30 Aug. 2022 Gandy’s grandmother, Karen Parson, said the family just wants to see justice for her, meaning an arrest and a conviction of Gandy’s killer. Desiree Stennett, Orlando Sentinel, 30 Aug. 2022 Other notes provided insight into the killer's mindset. Chris Harris, Peoplemag, 10 Aug. 2022 Gary Ramirez was linked to the 1982 killing of Karen Stitt, 15, after a Sunnyvale police detective was alerted to the killer's possible identity last year, according to court documents filed in Santa Clara County. Tim Stelloh, NBC News, 10 Aug. 2022 Flitting through realities, Kirby and Dan race to end the killer's reign of terror in a series that masterfully blends together sci-fi, horror, and feminist drama. Jace Lacob, EW.com, 25 July 2022 Investigators performed a handwriting comparison to confirm the notes were written by Gabe’s ex-boyfriend and alleged killer, 27-year-old Marshall Curtis Jones, according to CBS News. Susie Neilson, San Francisco Chronicle, 9 July 2022 Some survived the Colorado hammer killer's barbaric attacks. Kc Baker, PEOPLE.com, 6 July 2022 See More Word History
First Known Use
Noun
15th century, in the meaning defined at sense 1
Adjective
1951, in the meaning defined at sense 1
Phrases Containing killer
Kids Definition
killer 1 of 2
noun
kill·er ˈki-lər
: someone or something that takes the life of a person or animal
killer
2 of 2adjective
1
: very impressive or effective
a killer smile
2
: very difficult
a killer exam
3
: causing death or ruin a killer tornado
killer 1 of 2
noun
1
as in headache
a dull, unpleasant, or difficult piece of work weeding out that overgrown garden is going to be a killer Synonyms & Similar Words
Relevance
- headache
- job
- beast
- bear
- burden
- chore
- effort
- labor
- load
- nuisance
- heavy lifting
- strain
- grind
- trouble
- sweat
- drudgery
- lucubration
- weight
- bother
Antonyms & Near Antonyms
- setup
- breeze
- snap
- duck soup
- cinch
- kid stuff
- child's play
2
as in murderer
a person who kills another person gunned down by hired killers Synonyms & Similar Words
- murderer
- assassin
- torpedo
- cutthroat
- homicide
- butcher
- slayer
- manslayer
- executioner
- slaughterer
- triggerman
- murderess
- massacrer
- hit man
- bravo
killer
2 of 2adjective
1
as in lethal
likely to cause or capable of causing death killer viruses that claimed millions of lives Synonyms & Similar Words
- lethal
- deadly
- fatal
- infectious
- poisonous
- murderous
- infective
- toxic
- terminal
- harmful
- fell
- dangerous
- deathly
- mortal
- destructive
- pernicious
- pestilent
- baleful
- vital
- virulent
- threatening
- hazardous
- serious
- menacing
- bloody
- deleterious
- ugly
- injurious
- jeopardizing
- noxious
- risky
- sublethal
- grave
- baneful
- pestilential
- perilous
- sanguinary
- unhealthy
- truculent
- sanguine
- grievous
- internecine
- unsound
- parlous
Antonyms & Near Antonyms
- healthy
- beneficial
- nonlethal
- healthful
- nonfatal
- beneficial
- restorative
- remedial
- wholesome
- salutary
- curative
- useful
- tonic
- advantageous
- salubrious
- corrective
- safe
- alleviative
- nontoxic
- nonpoisonous
2
as in difficult
requiring considerable physical or mental effort a killer exercise program guaranteed to whip you into shape Synonyms & Similar Words
- difficult
- challenging
- tough
- formidable
- demanding
- hard
- rigorous
- murderous
- complicated
- heavy
- testing
- rugged
- sweaty
- tall
- severe
- rough
- intricate
- stiff
- exhausting
- backbreaking
- uphill
- elusive
- exacting
- complex
- serious
- painful
- hellacious
- grueling
- involved
- herculean
- pick-and-shovel
- effortful
- strenuous
- arduous
- laborious
- annoying
- brutal
- bruising
- problematic
- abstract
- gruelling
- hairy
- grim
- toilsome
- stubborn
- trying
- tricky
- oppressive
- thorny
- knotty
- spiny
- tight
- troublesome
- taxing
- moiling
- insoluble
- labored
- abstruse
- recondite
- ticklish
- opaque
- Augean
- stressful
- strict
- problematical
- bothersome
- burdensome
- distressing
- cruel
- irksome
- vexatious
- onerous
- stringent
- inhuman
- grievous
Antonyms & Near Antonyms
- cheap
- light
- simple
- soft
- easy
- clear
- mindless
- achievable
- uncomplicated
- effortless
- facile
- elementary
- soothing
- doable
- smooth
- gentle
- comforting
- undemanding
- friendly
- painless
- manageable
- relaxed
- accessible
- user-friendly
- idiotproof