ill
adjective
ill
1 American
[il]
/ ɪl /
adjective
worse,
worst,
iller,
illest
-
of unsound physical or mental health; unwell; sick.
She felt ill, so her teacher sent her to the nurse.
-
objectionable; unsatisfactory; poor; faulty.
ill manners.
-
ill feeling.
-
of ill repute.
- Synonyms:
- iniquitous, wrong
- Antonyms:
- good
-
ill fortune.
-
of inferior worth or ability; unskillful; inexpert.
an ill example of scholarship.
-
His mom is the illest cook.
noun
-
ills
plural
-
an unfavorable opinion or statement.
I can speak no ill of her.
-
harm or injury.
His remarks did much ill.
- Synonyms:
- misery, affliction, pain, hurt
-
trouble, distress, or misfortune.
Many ills befell him.
- Synonyms:
- calamity
-
evil.
to know the difference between good and ill.
- Synonyms:
- depravity
-
sickness or disease.
- Synonyms:
- affliction, illness
adverb
-
in an ill manner.
-
unsatisfactorily; poorly.
It ill befits a man to betray old friends.
-
in a hostile or unfriendly manner.
-
unfavorably; unfortunately.
-
with displeasure or offense.
-
faultily; improperly.
-
with difficulty or inconvenience; scarcely.
Buying a new car is an expense we can ill afford.
idioms
I'll
2
American
[ahyl]
/ aɪl /
ill.
3
American
abbreviation
-
illustrated.
-
illustration.
-
illustrator.
-
most illustrious.
Ill.
4
American
abbreviation
ill
1
British
/ ɪl /
adjective
-
(usually postpositive) not in good health; sick
-
characterized by or intending evil, harm, etc; hostile
ill deeds
-
causing or resulting in pain, harm, adversity, etc
ill effects
-
ascribing or imputing evil to something referred to
ill repute
-
promising an unfavourable outcome; unpropitious
an ill omen
-
harsh; lacking kindness
ill will
-
not up to an acceptable standard; faulty
ill manners
-
unable to relax; uncomfortable
noun
-
evil or harm
to wish a person ill
-
a mild disease
-
misfortune; trouble
adverb
-
badly
the title ill befits him
-
with difficulty; hardly
he can ill afford the money
-
not rightly
she ill deserves such good fortune
Ill.
2
British
abbreviation
I'll
3
British
/ aɪl /
contraction
ill
More Idioms
Grammar
See well 1.
Usage
What are other ways to say ill? The adjective ill is defined as “evil; wicked; bad.” However, it’s not used in exactly the same way as any of those synonyms! Learn the difference among these terms on Thesaurus.com.
Synonym Usage
Ill, sick mean being in bad health, not being well. Ill is the more formal word. In the U. S. the two words are used practically interchangeably except that sick is always used when the word modifies the following noun: He looks sick ( ill ); a sick person. In England, sick is not interchangeable with ill, but usually has the connotation of nauseous: She got sick and threw up. sick, however, is used before nouns just as in the U. S.: a sick man.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of ill1
1150–1200; Middle English ill ( e ) (noun and adj.) < Old Norse illr (adj.) ill, bad
Origin of ill.3
ill. ( def. 4 ) < Latin illustrissimus
Explanation
If you're ill, you're unwell, or sick. Being ill is a good excuse for missing work or school. You might get ill after being sneezed on by someone with a cold; or eating street food in a foreign country; or for no reason that you can point to. People can be mentally ill as well as physically ill, from depression or anxiety among other ailments. Ill can also mean "bad" in various ways, including when you suffer ill effects from going too long without sleep, or exercise ill judgment when you buy $500 worth of lottery tickets.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
My closest friend of more than 40 years is terminally ill, with most likely less than a year to live.
From MarketWatch ● Sep. 25, 2026
In addition to worrying about his ill daughter, Bach mutters and growls about the Prussian troops rampaging through his town.
From The Wall Street Journal ● Sep. 24, 2026
From a combination of mold exposure and severe burnout from filming “After Midnight” on weekdays and performing in different cities on weekends, she fell ill for months and was forced to take a break.
From Los Angeles Times ● Sep. 22, 2026
Many universities recommend planning ahead in case you feel ill and need some medical help at some point, especially if you're living away from home.
From BBC ● Sep. 22, 2026
I felt like something ill was festering in my stomach, and my head felt like a piñata stuffed with cotton balls.
From "Summer of the Mariposas" by Guadalupe García McCall
"I guess I'll leave that as a surprise," he said.
From BBC ● Sep. 27, 2026
I’ll probably get up around 1 or 2 p.m. because I stay up until about 3 or 4 a.m.
From Los Angeles Times ● Sep. 25, 2026
Yes, I’ll say it for you: Beware the hype over the next teenage soccer phenom.
From The Wall Street Journal ● Sep. 24, 2026
I’ll let you in on another bit of digital journalism that always holds true: Questions explored in commentaries are either unanswerable or the answer is “no.”
From Salon ● Sep. 23, 2026
“So, starting tomorrow, I’ll find out as much as I can about all three,” I tell Rue.
From "Split the Sky" by Marie Arnold
"She then cancelled the wedding saying she was ill. But I was 50 that year so my partner and I still wanted to go to Turkey."
From BBC ● Sep. 2, 2026
"He was critically ill. His heart stopped as soon as he arrived. We had to perform CPR," said lead author Ankit Bharat, a thoracic surgeon at Northwestern University.
From Science Daily ● Mar. 18, 2026
"She was only 28. It wasn't like she was ill. She was here one day and gone the next, we didn't even get to say goodbye."
From BBC ● Aug. 8, 2025
"Tatler, you should be ashamed putting this on the cover. A child would have done a better job. I’m so angry you've done this whilst she is so ill. Shame on you."
From Salon ● May 23, 2024
“Please, I am very ill. It is my stomach. May I take the rest of the day off and visit the infirmary?”
From "First They Killed My Father: A Daughter of Cambodia Remembers" by Loung Ung
His family moved to Decatur, Ill., where Archer-Daniels-Midland was based, after the agricultural giant named him to its board in 1991.
From The Wall Street Journal ● Sep. 19, 2026
The company expects eventually to increase annual production capacity at its plant in Normal, Ill., to 215,000 vehicles, adding potentially another 300,000 in capacity through its plant in Stanton Springs, Ga.
From MarketWatch ● Sep. 17, 2026
The Carbondale, Ill., wonder, who grew up fishing a pond in his backyard, rocketed up the sport with his wizardry for forward-facing sonar.
From The Wall Street Journal ● Aug. 29, 2026
“I just wanted to try it out,” she said from the warning track at Robin Roberts Field in Springfield, Ill., where the league was set to play its first games this weekend.
From Los Angeles Times ● Aug. 2, 2026
I was born on March 9, 1943 in Chicago, Ill. U.S.A.
From "Endgame" by Frank Brady
Time, perhaps, to question whether he's got the answers to the myriad ills of his team.
From BBC ● Sep. 20, 2026
To remedy these ills, the court needs top-to-bottom reform.
From Slate ● Jul. 29, 2026
An experience completely ignorant to the ills of modern football, to politics, ticket prices or hydration breaks.
From BBC ● Jun. 21, 2026
Ultimately, a ballot initiative won’t cure the ills that plague healthcare in the United States, said the Lown Institute’s Saini.
From Los Angeles Times ● Jun. 10, 2026
He was fed up with traveling through exotic countries selling shark-fin aphrodisiacs, ginseng to cure all ills, carved Eskimo statues, stuffed Amazonian piranhas, and chinchillas for ladies’ coats.
From "The House of the Spirits: A Novel" by Isabel Allende
"If you have a generally iller population, that's not good for the residents, it's not good for productivity, it's not good for the economy.'"
From BBC ● May 25, 2023
This gave him an unnatural appearance and made him look iller than ever.
From The New Yorker ● Dec. 30, 2019
He got iller and iller and iller, and of course he died in the beginning of 2015 when some of the other things had started appearing in the press.
From BBC ● Nov. 23, 2016
Still, in his older, iller years, he's become kinder, even to himself, and though he wished he'd done some stuff better, he could live with it.
From The Guardian ● Jun. 23, 2012
Still, if this be snow in earnest," he added with a cheerier tone, "it may rid us of these vermin, who'll find provand iller to get every extra day they bide.
From John Splendid The Tale of a Poor Gentleman, and the Little Wars of Lorn by Neil Munro
The Black neighborhoods like Baldwin Hills Estates, Ladera Heights and View Park all sit hillside with some of the illest views in the city.
From Los Angeles Times ● Apr. 13, 2026
His wife was told she should prepare for the worst, with staff describing her husband as "one of the illest people they'd ever seen".
From BBC ● May 21, 2024
Rapper Travis Scott told his nearly 12 million followers on X, the site formerly known as Twitter, that Monday “might be one for the illest days in women’s sports historyyyyyyy.”
From Seattle Times ● Apr. 2, 2024
Blaze is just one of the illest low heads.
From Salon ● Mar. 6, 2021
Not knowing is worse than the very illest news.
From Grey Town An Australian Story by Gerald Baldwin
In humans, mutations in the FBXW7 gene in breast cancer are associated with worse prognosis - paralleling the change seen in cats.
From Science Daily ● Sep. 27, 2026
The United Nations' top official for refugees warned on Friday that conditions for long-displaced people in Western Sahara were getting worse and that their humanitarian needs were starkly underfunded.
From Barron's ● Sep. 25, 2026
Citizens who aren’t likely to notice when their local newspaper becomes a bit more bare-bones, or that the already byzantine healthcare system becomes slightly harder to navigate, will definitely notice when their lunch gets worse.
From Salon ● Sep. 25, 2026
That would solve her immediate problem of finding her way home but create an even worse one by erasing her recall of her most precious friendship.
From The Wall Street Journal ● Sep. 24, 2026
But I’m scared I’d make it even worse.
From "Keeping Pace" by Laurie Morrison
When a clown’s only trick is shouting into a live microphone, the absolute worst thing that can happen is for the cameras to simply turn off.
From Salon ● Sep. 27, 2026
And worst of all, USC’s defense still couldn’t get a stop.
From Los Angeles Times ● Sep. 27, 2026
Dobbin added that one senior official at the Home Office told colleagues that the conditions were the worst he had seen in 20 years.
From BBC ● Sep. 25, 2026
“The piano world,” the author writes, “is, in many ways, the worst of the canon-worshipping repertoires, a leftover of Clara’s own legacy.”
From The Wall Street Journal ● Sep. 25, 2026
I squeezed my eyes shut and prepared for the worst.
From "Rump: The (Fairly) True Story of Rumpelstilskin" by Liesl Shurtliff
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
