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:
In July 2025, 247 pupils and staff at the nursery were found to have abnormally high blood lead levels after children began falling ill.
From BBC ● Oct. 17, 2026
Kenya's first victim has not been named but was referred to as a 40-year-old businessman, who fell ill around a month ago.
From Barron's ● Oct. 17, 2026
It began with small accounts on social media speculating or claiming that Talarico was out not because he was physically ill but because he was mentally ill.
From Slate ● Oct. 16, 2026
Despite scans and biopsies, experts could not figure out why she was ill.
From Los Angeles Times ● Oct. 15, 2026
Maggie was troubled, “I … twice dreamt that you were very, very ill; and I waked each time weeping bitterly.”
From "American Spirits" by Barb Rosenstock
“You’re asking the question because implicitly you assume that I’ll have dual loyalties, right?”
From Slate ● Oct. 19, 2026
“Later I will get a deal, and I’ll be able to pay back the investment,” she promised.
From The Wall Street Journal ● Oct. 19, 2026
"I'd beaten him on the outside a couple of times so I thought I'll come inside and just let rip," Madueke said.
From BBC ● Oct. 18, 2026
I really like their knishes, or I’ll get a half-sandwich and soup.
From Los Angeles Times ● Oct. 16, 2026
Next summer I’ll be in Old Town Alexandria, seeing everything Jillian wants to share with me.
From "Legendary Frybread Drive-In" by Cynthia Leitich Smith
"There was a glint of fear. They were dour. This was something more than someone being ill. It was something that affected them."
From BBC ● Aug. 6, 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 said: "It was a shock because my father was always a big, strong man, so he was never ill. He never used to take time off sick from work."
From BBC ● Dec. 15, 2025
“I was genuinely surprised to see how many of you wrote letters to the judges, telling him I was mentally ill. Like my mother,” she said.
From Salon ● Oct. 27, 2024
"I was ill. I could have treated myself if I'd had the medicine I have now."
From "The Hunger Games" by Suzanne Collins
In June, real-estate investor Justin Smith closed on a duplex in Roscoe, Ill. — about 90 miles west of Chicago — for $250,000.
From MarketWatch ● Oct. 17, 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 Vittitoes were paying more than $13,000 a year on their home in Washington, Ill., outside Peoria.
From The Wall Street Journal ● Sep. 13, 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 was born on March 9, 1943 in Chicago, Ill. U.S.A.
From "Endgame" by Frank Brady
Like the Tech Right, these men see noble masculinity as the solution to most of society’s ills.
From Slate ● Oct. 15, 2026
De Zerbi may feel he has addressed some of the ills in a squad that has finished 17th in the Premier League two seasons in succession.
From BBC ● Aug. 22, 2026
As Dan Kois illustrates in this ode to kicking back with friends, spending unstructured time together is a blessedly simple cure to the ills of modern life.
From Slate ● Jul. 10, 2026
The Swiss are largely well-governed, and the country’s appeal is understandable to people who want to escape the tax rates and other ills that are common elsewhere in Europe.
From The Wall Street Journal ● Jun. 14, 2026
She used religion as a therapy for the ills of the world and of herself, and she changed the religion to fit the ill.
From "East of Eden" by John Steinbeck
"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
Last year began with my being ill, kept on with my being iller, then I was unwell, followed by being poorly with a tiny interlude of infirmity.
From The Guardian ● Aug. 15, 2012
The more she reflected upon what her possibilities had been and how she had misused them, the iller and the more distressed she got.
From Stories by American Authors, Volume 6 by Various
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
ITEP's conclusion is that the middle fifth of households are, on average, around $1,700 worse off in 2026 than they would have been, while the poorest fifth are around $750 worse off.
From BBC ● Oct. 20, 2026
After Roosevelt’s election in November, things got worse.
From The Wall Street Journal ● Oct. 19, 2026
That could have been better, or it could have been worse.
From MarketWatch ● Oct. 19, 2026
Moreover, as the famous saying goes, this is worse than a crime: It’s a mistake.
From Slate ● Oct. 19, 2026
But there could be worse things, Clare decided.
From "The Undead Fox of Deadwood Forest" by Aubrey Hartman
Among worst performers on Japan’s benchmark index, Fujikura falls 3.4%, SoftBank Group 9984 -5.43%decrease; red down pointing triangle drops 3.3%, and Resona Holdings 8308 -3.32%decrease; red down pointing triangle sheds 2.7%.
From The Wall Street Journal ● Oct. 20, 2026
While the S&P 500 gained 31.29 points, or 0.41%, to 7690.73 and the tech-heavy Nasdaq composite jumped 290.85 points, or 1.11%, to 26430.89, regaining some of the losses from its worst week since June.
From The Wall Street Journal ● Oct. 19, 2026
And on Monday, their worst fears appear to have been realised.
From BBC ● Oct. 19, 2026
Shares of the chip maker rise as the market gets over the worst of its AI spending fears.
From Barron's ● Oct. 19, 2026
She gazed at Deadwood with dreamlike curiosity, unlike most people, who peered at Clare’s tangled woods with dread, or disgust, or, worst of all, as if it were something they could own.
From "The Undead Fox of Deadwood Forest" by Aubrey Hartman
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