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:
To identify the source of the outbreak, FDA officials conducted a traceback investigation — a process in which officials trace food that made people ill all the way back to the farm or production facility.
From Los Angeles Times ● Aug. 11, 2026
Another took responsibility for treating and feeding animals that had fallen ill.
From BBC ● Aug. 11, 2026
Despite a battery of tests, including a contrast CT scan and bone marrow biopsy, experts could not determine what was making Jackie critically ill.
From Los Angeles Times ● Aug. 10, 2026
He said his work selling stair lifts meant he saw "a lot of ill people".
From BBC ● Aug. 4, 2026
But then it occurred to me that she must be very ill to miss a commitment like this.
From "The Red Car to Hollywood" by Jennie Liu
“Bring me an idea and I’ll explain why it can’t, shouldn’t, and won’t happen,” the site said, followed by a box encouraging users to type in a query.
From Los Angeles Times ● Aug. 11, 2026
As Letterman said after Future Islands, I’ll take all of that you’ve got.
From The Wall Street Journal ● Aug. 10, 2026
"It's quite common for bars to provide free Wi-Fi with routers, so I'll provide free tokens," or units of AI usage, bar owner Song De told AFP.
From Barron's ● Aug. 10, 2026
"I'll be honest, it's like an addiction now," he tells me.
From BBC ● Aug. 9, 2026
Unlike Father, I’ll tell my son about the land rush journey.
From "Will’s Race for Home" by Jewell Parker Rhodes
"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
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 walked into the facility healthy and feeling fine, and within 24 hours I became severely ill. I had severe burning in my face, tremors, twitching; I felt like I was being electrocuted.”
From Los Angeles Times ● Mar. 12, 2025
"They may not mean me ill. Men have looked at women since time began, perhaps it is no more than that."
From "A Clash of Kings" by George R.R. Martin
SPRINGFIELD, Ill. — Isabella Villareal practiced with the Los Angeles Queens for the first time on Saturday morning, hours before the team’s first game.
From Los Angeles Times ● Aug. 2, 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
A native of Princeton, Ill., a city of about 8,000 people, Rowe’s job included easing tensions between China and the U.S. farmer.
From The Wall Street Journal ● Jul. 1, 2026
The North Chicago, Ill., company has said it expects combined revenue from Rinvoq and fellow autoimmune drug Skyrizi will top $31 billion this year.
From The Wall Street Journal ● Jun. 22, 2026
I was born on March 9, 1943 in Chicago, Ill. U.S.A.
From "Endgame" by Frank Brady
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
As Norway advance, is Wright correct about Scottish football's ills?
From BBC ● Jul. 7, 2026
But no leader has been able to fix the country’s economic ills, which have been compounded by the decision to leave the European Union and a borrowing binge during Covid-19.
From The Wall Street Journal ● May 8, 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
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
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
This, in turn, was the very thing to keep him but ill at ease with himself, and iller at ease, if not at downright loggerheads, with everybody else.
From The Red Moccasins A Story by Morrison Heady
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
Not knowing is worse than the very illest news.
From Grey Town An Australian Story by Gerald Baldwin
“It’s something we’ve known about, but it hasn’t gotten worse over the years,” Rushing said.
From Los Angeles Times ● Aug. 12, 2026
“The problem today is worse than it was 10 years ago,” says Chris Cornell, founder of Manhead, an official merch company for artists like Jelly Roll and Fall Out Boy.
From The Wall Street Journal ● Aug. 11, 2026
But other times we have to stop because of discomfort or panic, a reality that affects us for the worse.
From Slate ● Aug. 10, 2026
If you could even find a Ramones T-shirt in the ’70s or ’80s, you weren’t going to wear it anywhere besides a Ramones concert unless you wanted to find yourself in an argument, or worse.
From Salon ● Aug. 10, 2026
To make things worse, he squirmed his rear end around until his tail was hanging over the back of the spring seat.
From "Summer of the Monkeys" by Wilson Rawls
But this August 13 comes amid one of Cuba's worst crises in living memory, with acute shortages of food and water, and chronic power cuts.
From Barron's ● Aug. 11, 2026
The Angels have the worst record in the major leagues and are on pace for the first 100-loss season in franchise history.
From Los Angeles Times ● Aug. 11, 2026
But when the book came out, I just felt like the world’s worst son.
From The Wall Street Journal ● Aug. 11, 2026
In 2023, the country saw its worst wildfire season in history in terms of the total area burned.
From BBC ● Aug. 10, 2026
Those were the worst times during our whole long trek, the days of hunger.
From "An Elephant in the Garden" by Michael Morpurgo
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.
