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 2020, he announced that he had been severely ill as a result of lithium poisoning: a treatment aimed at stabilising his moods.
From BBC ● Jul. 27, 2026
The dose was low enough that the mothers did not become significantly ill.
From Science Daily ● Jul. 25, 2026
Last year, two women became critically ill at a longevity conference in Las Vegas after they received peptide injections at a booth.
From The Wall Street Journal ● Jul. 24, 2026
One firefighter died after falling ill while battling the flames in Sicily, the interior minister said.
From Barron's ● Jul. 24, 2026
“I have to agree with Alter,” Bailey said, looking rather ill.
From "The City Beautiful" by Aden Polydoros
Tell me who you’re putting on these groups, he said, and I’ll tell you what they’ll say.
From The Wall Street Journal ● Jul. 28, 2026
"My goals and assists are really important so I'll make sure I'm right at it," she adds.
From BBC ● Jul. 28, 2026
Starting Aug. 4, I’ll be in your inbox every Tuesday as I officially take the reins as Don’t Short Yourself’s regular writer.
From MarketWatch ● Jul. 28, 2026
When they’re done talking, I’ll ask, “Can I share my perspectives on this?”
From Los Angeles Times ● Jul. 28, 2026
“Thanks for the fries. I’ll pay you back.”
From "Red Flags and Butterflies" by Sheryl Azzam
"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
"I was violently ill. I was sweating. I was cold. I was shaking. I was vomiting for about four or five days."
From BBC ● Jan. 5, 2026
"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
“We have so appreciated all of the prayers and support from friends who knew he was very ill. Although it is hard for us to say goodbye, his peaceful passing was a blessing for him.”
From Los Angeles Times ● Apr. 16, 2024
“Beowulf is also ill. He claims to have a headache in his leg.”
From "The Interrupted Tale" by Maryrose Wood
Calamos Investments is based in Naperville, Ill., and manages about $52 billion in assets through various strategies.
From MarketWatch ● Jul. 27, 2026
Grand Detour, Ill.: John Deere’s “self-polishing” steel blade allowed settlers to slice through the sticky Midwest sod, unlocking the agricultural potential of the American heartland.
From The Wall Street Journal ● Jul. 9, 2026
Ben Zwief, an adviser in Lake Forest, Ill., cites the example of a client with $50,000 in credit-card debt at a 20% interest rate.
From MarketWatch ● Jul. 2, 2026
Gleeson, of St. Joseph, Ill., set out to buy a new car six years ago, but couldn’t find what he wanted amid the pandemic vehicle shortages.
From The Wall Street Journal ● Jun. 6, 2026
I was born on March 9, 1943 in Chicago, Ill. U.S.A.
From "Endgame" by Frank Brady
To remedy these ills, the court needs top-to-bottom reform.
From Slate ● Jul. 29, 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
Complicating Iran’s recovery is a host of economic and social ills that predate the recent war, including a worsening banking crisis.
From The Wall Street Journal ● Apr. 16, 2026
"Their energy and creativity are invaluable. Investing in their education, training, and entrepreneurship is essential for peace and for preventing the loss of talent and the spread of social ills," he said.
From BBC ● Apr. 16, 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
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
‘You’re sorry that we are not any iller, aren’t you, Dr. Hurst?’ she remarked.
From The Youngest Girl in the School by Sharp, Evelyn
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
It’s one of the illest, if not the illest Caribbean food spots in the city.
From Washington Post ● Aug. 22, 2022
There was just a little milk that was reserved for the illest patients, no butter or bread.
From Field Hospital and Flying Column Being the Journal of an English Nursing Sister in Belgium & Russia by Thurstan, Violetta
Repeated images looking worse for wear will not help his cause and may put off any potential suitors.
From BBC ● Jul. 29, 2026
But I get it: You are afraid you have left some giant loophole in your estate planning that could cause delays or worse after you’re gone.
From MarketWatch ● Jul. 29, 2026
The contrasts become worse in looking at Vance and Obama’s second books, both of which were more obviously written with an eye toward running for higher office.
From Salon ● Jul. 29, 2026
The Times quoted an unnamed "senior football figure" calling the plan "potentially much worse than the European Super League", as it would have an impact on all levels of football across the globe.
From Barron's ● Jul. 28, 2026
From the sound of his cough and his wheezing, we could tell that Karli was getting worse all the time.
From "An Elephant in the Garden" by Michael Morpurgo
Isabel Díaz Ayuso, the leader of Madrid’s local government, earlier this week described the Madrid wildfires as perhaps “the worst natural catastrophe in Spain’s history.”
From The Wall Street Journal ● Jul. 29, 2026
As Sara emerges as the ever-dwindling group’s heroine, Max goes from being the bossy but loveable Alpha Friend to She Who Must Be Obeyed, even as she makes the worst decisions possible.
From Los Angeles Times ● Jul. 29, 2026
In Somerset, farmers have described this as the worst drought in 50 years, leaving crops struggling.
From BBC ● Jul. 29, 2026
As French firefighters struggle to contain the worst wildfires in living memory with just 12 aerial water bombers, production of the iconic aircraft creaks along half a world away in a Canadian factory.
From Barron's ● Jul. 28, 2026
Knowing it was the worst thing to do, Renn leaned forward and peered through the gap.
From "Wolf Brother" by Michelle Paver
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.
