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:
Those include the costs of medical and long-term care if one partner falls into ill health, as well as disputes over the aforementioned expenses and inheritance.
From MarketWatch ● Jul. 24, 2026
Mentally he is quite fragile, and when he becomes physically ill from a bacterial infection, he suffers a mental breakdown.
From The Wall Street Journal ● Jul. 23, 2026
Interior Minister Matteo Piantedosi said a firefighter died after falling ill while battling the flames.
From Barron's ● Jul. 22, 2026
Natalie Fleet says she has stepped down as safeguarding minister after finding the role "overwhelmingly triggering", telling the BBC that it was making her ill.
From BBC ● Jul. 22, 2026
He was dressed in golfing clothes and looked slightly ill at ease.
From "Mountains Beyond Mountains" by Tracy Kidder and Michael French
I’ll grab a yogurt for breakfast and then head out the door, on my way to Fryman Canyon for a little morning hike.
From Los Angeles Times ● Jul. 24, 2026
"I'll go to social media before Google or somewhere else. Everyone is already talking about it," affirms Major.
From BBC ● Jul. 24, 2026
"I'm thrilled to say welcome back to the White House, and maybe I'll see you again next year," said Trump.
From Barron's ● Jul. 23, 2026
And with that, I’ll leave you be until tomorrow.
From Slate ● Jul. 23, 2026
“I’m not sure yet. But I’ll let you know,” she replies sweetly.
From "Split the Sky" by Marie Arnold
"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 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
“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
"When I was in hospital, the Post Office sent their own doctors to see if I was actually ill. And that's what really hurt the most," she recalled.
From BBC ● Apr. 8, 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
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
Cigars and Stripes BBQ in Berwyn, Ill., features a Muffler Man smoking a cigar and holding a jumbo bottle of barbecue sauce.
From Los Angeles Times ● May 12, 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
An experience completely ignorant to the ills of modern football, to politics, ticket prices or hydration breaks.
From BBC ● Jun. 21, 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
A Google user experience team two years later detailed ills affecting viewer well-being, based on external research.
From The Wall Street Journal ● Apr. 29, 2026
We asked for a sign from heaven, and the sign came to cut across the open sea to Euboia, and lose no time putting our ills behind us.
From "The Odyssey" by Homer
"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
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 Munro, Neil
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
"It really impacts a lot on my sleep habits," she told Sam Murphy on the Pop Pod, external, saying the pain had got "progressively worse over the past couple of years".
From BBC ● Jul. 24, 2026
Read: Texas Instruments shares are sliding, and its rival is doing even worse.
From MarketWatch ● Jul. 23, 2026
"Regulation should improve products, not make them worse," Google's Kent Walker said in a statement.
From Barron's ● Jul. 23, 2026
Silver production fared worse, falling nearly 13% on year to 10.9 million ounces due to a combination of lower grades and a decrease in processed volumes, it said.
From The Wall Street Journal ● Jul. 22, 2026
Grandma’s table sat beside the donut cart, which only made my wanting worse.
From "Bye Forever, I Guess" by Jodi Meadows
Tesla’s earnings commentary wasn’t enough to justify the company’s big-spending ways, leading to the stock’s worst post-earnings performance ever Thursday.
From MarketWatch ● Jul. 23, 2026
The film is at its worst when it forces plot developments to push the two leads together.
From The Wall Street Journal ● Jul. 23, 2026
IBM shares fell 25% on July 14 following a preliminary disclosure of the results, marking the worst day in its history.
From The Wall Street Journal ● Jul. 22, 2026
Watt, who has since joined Turkish club Samsunspor, received a four-match suspension, having described it as "the worst VAR decision in history".
From BBC ● Jul. 22, 2026
The worst was his I-don’t-care tone, the one he uses when he wants me to know that I’m not worth his time.
From "Red Flags and Butterflies" by Sheryl Azzam
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.