ill

ill — adjective

1. Experiencing a disease or medical condition that keeps your body from working no

1.adjectiveA2
Definition

Experiencing a disease or medical condition that keeps your body from working normally.

Example

Tunde was too ill to go to school on Monday, so he stayed in bed.

too ill to [verb]

The old cat became ill after eating something from the rubbish bin.

Common collocations
  • ill with
  • fall ill
  • be taken ill
  • critically ill
  • terminally ill
  • mentally ill
Synonyms
  • sick

    More common in American English; 'sick' can also mean feeling nauseous, while 'ill' usually refers to a broader condition.

  • unwell

    Less severe and more polite; often used in formal or careful language.

  • poorly

    Informal British English, used mainly in spoken language.

Antonyms
  • well

    The most common opposite; simply means in good health.

  • healthy

    Describes a long-term state of good health rather than the temporary absence of illness.

Grammar Patterns

be ill

be ill with [illness]

fall ill

be taken ill

Usage Note

In modern English, 'ill' is usually placed after a linking verb ('be', 'feel', 'become') rather than directly before a noun. Saying 'an ill man' sounds old-fashioned; 'a sick man' is far more natural. One common exception is the fixed phrase 'ill health'.

Common Mistakes

She is an ill woman.
She is ill.
In everyday English, 'ill' is not placed before a noun (except in fixed phrases like 'ill health').
He was ill of a fever.
He was ill with a fever.
The correct preposition after 'ill' is 'with', not 'of'.

2. Having a negative, damaging, or morally wrong character — used of effects, inten

2.adjectiveC1
Definition

Having a negative, damaging, or morally wrong character — used of effects, intentions, fortune, or reputation.

Example

The factory closures had ill effects on the whole town's economy.

ill effects

Despite the heated debate, Faisal bore no ill will toward the new manager.

ill will

Common collocations
  • ill will
  • ill effects
  • ill health
  • ill fortune
  • ill repute
  • ill omen
Synonyms
  • bad

    The everyday equivalent; less formal and far more versatile.

  • harmful

    Focuses on causing damage or injury specifically.

  • unfavorable

    Lighter in tone; describes conditions or outcomes that do not help.

Antonyms
  • good

    The general opposite in moral or qualitative contexts.

  • beneficial

    Specifically positive in effect or outcome.

Grammar Patterns

ill + noun

Usage Note

This sense is largely confined to a set of fixed noun phrases ('ill will', 'ill effects', 'ill health', 'ill fortune', 'ill repute'). In most other contexts, the everyday word 'bad' is preferred. Distinguish from sense 1: sense 2 always modifies a noun directly (attributive position), whereas sense 1 is used predicatively.

Common Mistakes

The food was ill.
The food was bad.
'Ill' meaning 'bad' is not used after a linking verb; it only appears before nouns in set phrases.
He has ill luck.
He has bad luck.
'Ill fortune' and 'ill luck' exist but are very formal; 'bad luck' is much more natural.

3. Producing a positive result even though the situation seems unfavorable — only u

3.adjective
Definition

Producing a positive result even though the situation seems unfavorable — only used in the traditional proverb about a wind that brings benefit to someone.

Example

Dewi lost her job but found a better one — an ill wind indeed.

it's an ill wind that blows nobody any good

The market crash hurt many investors, but some buyers picked up bargains. An ill wind indeed.

Grammar Patterns

it's an ill wind that blows nobody any good

Usage Note

This sense exists ONLY inside the fixed proverb 'it's an ill wind that blows nobody any good' (and shortened references to it). You cannot use 'ill' by itself to mean 'good' in any other context — that would confuse readers.

Common Mistakes

The concert was ill!' (attempting to mean 'good')
Use 'It's an ill wind that blows nobody any good' as a complete proverb.
'Ill' never functions as standalone slang for 'good'.
Idioms

Anger or dislike between people, often after a disagreement.

After the argument, there was bad feeling between Maya and her brother.

The team's loss created ill feeling among the players.

Feeling nervous, uncomfortable, or embarrassed in a situation.

Diego felt ill at ease during the formal dinner party.

Why does she look so ill at ease in the new office?

Anger or dislike between people, often after a disagreement.

The dispute caused ill feeling between the two neighbors.

Sara hoped to avoid any bad feeling at the family reunion.

Every bad situation brings some benefit to someone.

The storm canceled our trip, but it's an ill wind—we got to rest.

Losing his job was hard, but it's an ill wind; he started his own business.

ill — adverb

ill — noun

ill — prefix

Word family

Synonym discussion

Sense: adjective/1

All four words describe a state of poor health, but they differ in register, regional usage, and severity. 'Sick' is the most common word in American English and can refer to both general illness and the specific feeling of nausea ('I think I'm going to be sick'). 'Ill' is more common in British English and often implies a more serious or longer-lasting condition than 'sick', though the two overlap heavily. 'Unwell' is the most polite and least specific option — suitable when you do not want to give details ('She is feeling unwell'). 'Poorly' is an informal British word, used mainly in spoken language ('He looks poorly today'). In American English, 'poorly' is rare in this meaning. For temporary minor illness like a cold, American speakers strongly prefer 'sick'; British speakers might use either 'ill' or 'sick' depending on severity.

Common collocations

Nouns

Adverbs

  • seriously ill
  • critically ill
  • terminally ill
  • mentally ill
  • chronically ill

Phrases

  • fall ill
  • be taken ill
  • speak ill of
  • bode ill for
  • can ill afford
  • ill at ease

Prepositions

  • ill with
  • ill for

Etymology

Old NorseMiddle EnglishEnglish

The word 'ill' entered Middle English from Old Norse 'illr', meaning 'bad, evil, or difficult'. It gradually replaced the older English word 'evil' (from Old English 'yfel') in everyday use for describing poor health and bad conditions. While 'evil' retained its strong moral sense, 'ill' became the milder, more general word for anything unfavorable — from sickness to bad luck to improper behavior. The adverb and noun uses grew naturally from the same root.