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 early 1999, Lieberson put her career on hold to nurse her sister Alexis, who was gravely ill from breast cancer.
From The Wall Street Journal ● Jul. 28, 2026
The dose was low enough that the mothers did not become significantly ill.
From Science Daily ● Jul. 25, 2026
The delay could make it more difficult for ill people to remember all the foods they ate, “down to a single ingredient in a salad,” before they were stricken, Rimoin said.
From Los Angeles Times ● Jul. 24, 2026
It comes just a few days after Yates fell ill and vomited after stage 16's time trial.
From BBC ● Jul. 24, 2026
In 2010, 8.8 million people fell ill with TB, with 1.4 million deaths.
From "Mountains Beyond Mountains" by Tracy Kidder and Michael French
“I was a No. 10, what excites me is scoring goals…I was a leader on the pitch, and I’ll be a leader through what I’ve achieved.”
From The Wall Street Journal ● Jul. 28, 2026
I’ll return it to another Little Free Library when I’m finished.
From Salon ● Jul. 28, 2026
"My family and I are never going to heal from this trauma. I'll never be myself again and that's because of Robert Bush."
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
It’s been hard for me to accept that I’ll never again get to work alongside him, crafting another canoe, or tackling his mounds of paperwork.
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
"All of these people have had hepatitis C for more than three decades; some are very ill. A more proactive approach is critical to reaching and diagnosing those who remain unaware of their infection."
From BBC ● May 18, 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
Instead her stepmother turned the key in the lock and woke her, saying, “Beatrice is ill. She won’t be here today.”
From "Ash" by Malinda Lo
Calamos Investments is based in Naperville, Ill., and manages about $52 billion in assets through various strategies.
From MarketWatch ● Jul. 27, 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
The first R2s to roll off the company’s production line in Normal, Ill., are the performance version, starting at $57,990.
From Los Angeles Times ● Jun. 10, 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
In the video, Pratt stood outside Raman’s Silver Lake home and the city-owned Getty House in Hancock Park, where Bass lives, contending both are far removed from the urban ills that beset other Angelenos.
From Los Angeles Times ● May 21, 2026
But at the end, a veiled reference to the need to "support victims of some of the ills that, so tragically, exist in both our societies today".
From BBC ● Apr. 29, 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
She is evidently much iller than I thought.
From Victor's Triumph Sequel to A Beautiful Fiend by Southworth, Emma Dorothy Eliza Nevitte
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
A lingring death maye auaile my soule, but it is the illest of ills that can befortune my bodie.
From The Vnfortunate Traveller, or The Life Of Jack Wilton With An Essay On The Life And Writings Of Thomas Nash By Edmund Gosse by Gosse, Edmund
These animals also performed worse on tasks that tested their ability to remember where food had been located.
From Science Daily ● Jul. 29, 2026
For many working parents, she said, this was made worse by expensive nursery fees and the cost of covering children's hot lunches and after school clubs.
From BBC ● 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
But the carmaker issued a shock profit warning last month, saying that business in China was proving even worse than expected amid fierce competition and a sluggish economy.
From Barron's ● Jul. 29, 2026
That stitch in my side on my second hill run was ten times worse, and that went away no problem.
From "Keeping Pace" by Laurie Morrison
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 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
Even the best possible course is going to be one of the worst diseases most children ever go through.
From Los Angeles Times ● Jul. 28, 2026
"People say your 20s are the best years of your life and these are the worst years of my life, by far."
From BBC ● Jul. 28, 2026
“This was the reason we were sent here. Not to be the worst partner team in the history of forever, but because you and I are supposed to fix this.”
From "Glitch" by Laura Martin
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.
