ill
C1neutral (formal for 'sick'; slightly formal in extended/adverbial uses)
Definition
Meaning
suffering from a disease or poor health; not well.
Used to describe something harmful, unfavorable, or of poor quality (e.g., ill effects, ill will).
Linguistics
Semantic Notes
As an adjective predicating health, 'ill' is more formal than 'sick' in AmE, and is the standard term in BrE. Its other adjectival senses are always formal/literary.
Dialectal Variation
British vs American Usage
Differences
In BrE, 'ill' is the default word for unwell. In AmE, 'sick' is more common in everyday speech for physical illness, while 'ill' is more formal or used in fixed phrases.
Connotations
In both, extended senses ('ill-advised', 'ill-gotten') carry negative, often moral judgments.
Frequency
Higher frequency in BrE for health predicatives. Roughly equal in extended/adverbial uses.
Vocabulary
Collocations
Grammar
Valency Patterns
[BE/LOOK/FEEL] + illill + WITH + [disease]ill + [past participle] (e.g., ill-prepared)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “ill at ease”
- “it's an ill wind (that blows nobody any good)”
- “speak ill of”
- “take ill”
Usage
Context Usage
Business
Refers to detrimental effects or poor planning (e.g., 'The project suffered ill effects from the budget cuts').
Academic
Used in formal writing for health or negative abstract qualities (e.g., 'The study examined the social determinants of ill health').
Everyday
Primarily for describing sickness ('I can't come, I'm ill').
Technical
In medicine/psychology, used in terms like 'mentally ill', 'terminally ill'.
Examples
By Part of Speech
verb
British English
- 'To ill' is not a standard verb.
American English
- 'To ill' is not a standard verb.
adverb
British English
- The team was ill-equipped for the challenge.
- He can ill afford another mistake.
American English
- The plan was ill-conceived from the start.
- She spoke ill of her former colleague.
adjective
British English
- She's been ill for a week.
- The decision had ill consequences.
American English
- He was too ill to attend. (formal)
- They were ill-prepared for the storm.
Examples
By CEFR Level
- My brother is ill today.
- She didn't come to school because she felt ill.
- Several employees fell ill after the office party.
- He looked ill, so we called a doctor.
- The policy was ill-advised and caused public outrage.
- She suffers from chronic ill health.
- The remarks, however ill-intentioned, did not constitute harassment.
- One can ill imagine a more counterproductive strategy.
Learning
Memory Aids
Mnemonic
Think of a pill you take when you're ILL.
Conceptual Metaphor
BAD IS ILL / HARMFUL IS ILL (e.g., 'ill will', 'ill effects').
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating Russian 'злой' (evil/angry) as 'ill'. 'Ill' does not mean 'evil' or 'angry' by itself, only in compounds like 'ill-will'.
- Do not confuse with 'ill' as an adverb (e.g., 'ill-prepared'), which is not related to sickness.
Common Mistakes
- *'I have an ill' (incorrect – 'ill' is not a countable noun for sickness).
- Using 'ill' attributively for sickness (e.g., *'an ill child') is rare in AmE; 'a sick child' is preferred.
Practice
Quiz
Which of the following uses of 'ill' is most typical in American everyday speech?
FAQ
Frequently Asked Questions
In British English, 'ill' is standard for unwell; 'sick' often means nauseous. In American English, 'sick' is the common, neutral term for unwell; 'ill' is more formal or used in fixed expressions.
For the health sense, it's uncommon (e.g., 'an ill person' sounds formal/literary). It's standard in figurative compounds (ill effects, ill health, ill will).
Yes, but only in a formal/literary register, meaning 'badly' or 'with difficulty', and usually in combination with a past participle (e.g., ill-prepared, ill-suited) or fixed phrases ('can ill afford').
It is a standard clinical/legal term, but some prefer person-first language ('person with a mental illness'). Context and audience sensitivity are important.