ill

IL/ɪl/

Noun pluralills

16 meanings of ill

1
in poor healthadjective
Not healthy because of an illness of the body or the mind.
Like a plant that droops because it isn't getting what it needs.
Grandpa has been ill with the flu all week.
He stayed home from work because he was ill.
UsageSay ill with flu. Before a noun, people usually say sick: a sick child.
Similarsick, unwell, ailing, poorly, indisposed
Oppositewell, healthy, fit
2
adjective
Bad, unlucky, poorly done, or unwise.
Like a dark cloud that warns a storm is coming.
By some ill luck, the train was canceled again.
An ill wind blew the small boats off course.
UsageMostly in phrases like ill effects and ill fortune.
Similarbad, unfavorable, unlucky
Oppositegood, favorable
3
adverb
In a bad way, or not done well.
Don't speak ill of your friends behind their backs.
The hikers were ill prepared for the cold night on the mountain.
UsageUsed before words like received or advised: an ill-advised plan is an unwise plan.
Similarbadly, poorly
Oppositewell, favorably
Note
4
nouncountable or uncountable
A sickness or health problem in the body.
Like a sickness that stops part of your body from working right.
People once used this plant to treat coughs, colds, and other everyday ills.
Grandma believed hot soup could help with almost any ill.
UsageUsually ills, as in the ills of old age.
Similarailment, disease, malady, complaint, affliction
5
nouncountable or uncountable
Harm, trouble, or bad luck that happens to someone.
Like the troubles and bad luck that pile up during a hard time.
Money cannot protect you from every ill in life.
The town suffered many ills after the factory closed.
UsageUsually ills: the ills of modern life are its problems.
Similarmisfortune, trouble, problem, harm, evil
Note
6
unkindadjective
Showing unkind, harsh, or cruel feelings or plans toward someone.
She bore him no ill will after their argument.
The rescued dog was afraid of people after years of ill treatment.
UsageMostly in ill will and ill feeling: bad feelings toward someone.
Similarmalicious, hostile, malevolent, evil, unkind
Oppositegood, kind, benevolent, friendly
7
sick to stomachadjective
Feeling sick in your stomach, like you might throw up.
Like the sick feeling in your stomach on a fast, spinning ride.
The smell of the rotten fish made her feel ill.
He always feels ill on long, winding car trips.
UsageSay feel ill, or that something makes you ill.
Similarsick, nauseous, nauseated, queasy, unwell

Less common meanings

8
impressiveadjectiveslang
Very impressive and creative, often in music or dancing.
Like calling a song 'awesome' when it's really, really good.
Those are some ill beats on her new track.
The crew pulled off an ill routine at the dance battle.
UsageIn hip-hop talk it means very good: the illest is the best.
Similarsick, dope, wicked, tight, fresh
Oppositelame, wack, weak
Note
9
nouncountable or uncountable
Wrong or evil behavior, the opposite of good.
Like the bad side in a story, the opposite of doing good.
We all must choose between good and ill.
Old stories often show a battle between good and ill.
Similarevil, wrong, wickedness, sin, badness
Oppositegood, goodness, virtue, righteousness
10
adjectivearchaic
In old use, wicked or morally bad.
Like doing something so wrong that everyone blames you for it.
His ill conduct brought shame upon the whole family.
‘Go bring her. It is ill to keep a lady waiting.’
1999, George R.R. Martin, A Clash of KingsHere, ill means bad or wrong, so keeping a lady waiting is rude.
Note
11
awfuladjectiveslang
So bad that it almost makes you feel sick.
Like food so rotten it turns your stomach.
The bathroom at that gas station was so ill I almost gagged.
That movie was so ill we walked out halfway through.
UsageIt can mean very bad or very good, so listen to the tone.
Similarnasty, gross, foul, awful, terrible
Oppositenice, decent, pleasant
Note
12
bad-temperedadjectivedialectalAppalachia
In a bad mood and easily annoyed.
Like someone who is grumpy and snaps at everything around them.
Don't bother him before breakfast. He's always ill and snaps at people.
That dog is ill and will bite, so keep your hands away.
UsageHere it means angry, not sick. Others may not understand.
Similarbad, foul, sour, irritable, surly
Oppositegood, cheerful, sunny
Note
13
get aggressiveverbdatedintransitive
To act in a crazy, silly, or aggressive way.
Like getting in someone's face and acting tough for no real reason.
Stop illing, man. Nobody was trying to make fun of you.
D.M.C.: You been illin' lately. Run: So, I'm illin'. Am I illin'? Chillin'! You know what I'm sayin'? Chillin'.
1985, Ralph Farquhar, Krush GrooveHere, illin' means acting wild, foolish, or badly.
UsageUsually used in the form illin' or illing, as in quit illin'.
Similarrage, brawl, trip
Note
14
adverb
Hardly, or only with a lot of trouble or cost.
We can ill afford a new car this year.
She could ill spare the time, but she stayed to help anyway.
UsageMostly in can ill afford, meaning can hardly afford.
Similarhardly, scarcely, barely
Oppositewell, easily
Note
15
adverb
In an unkind way, or in a way that shows you think badly of someone or something.
My grandmother never spoke ill of anyone.
Please don't think ill of me for leaving the party early.
UsageSay speak ill of someone: say bad things about them.
Similarbadly, poorly, unfavorably
Oppositewell, favorably
16
nounslangUS
A strong illegal drug, also called PCP.

Practice

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Origin

It comes from Old Norse 'illr' (bad), which came into Middle English as 'ille' meaning evil or wicked.

Checked 1 Nov 2026 · 3 facts

English 'ill' derives from Old Norse 'illr' through Middle English 'ille'. en.wiktionary.org
Old Norse 'illr' meant 'bad'. en.wiktionary.org
Middle English 'ille' meant 'evil' or 'wicked'. en.wiktionary.org