unwell
[adjective]
Synonyms: ill, ailing, sick, sickly, under the weather (informal), unhealthy

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Antonyms: well
Related Idioms: out of sorts, under the weather
Related Words: rocky, shaky, wobbly, feeble, frail, infirm, weakly, ill, sick, qualmish, queasy, squeamish

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English Thesaurus: ill, sick, not very well, unwell, poorly, ...

[TahlilGaran] English Synonym Dictionary ▲

un‧well /ʌnˈwel/ adjective [not before noun]
formal ill, especially for a short time:
She had been feeling unwell.

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In everyday English, people usually say that someone is not well rather than unwell:
He didn’t come to school because he wasn’t well.

[TahlilGaran] Dictionary of Contemporary English ▲

unwell
adj.
VERBS appear, be, feel, look, seem, sound He complained of feeling unwell.
become | remain | make sb
ADV. extremely, really, very | a little, vaguely patients who just feel vaguely unwell
PREP. with You should delay vaccination if you are unwell with a fever.

[TahlilGaran] Collocations Dictionary ▲

ill [not before noun] especially British English suffering from a disease or not feeling well:
Her mother is seriously ill in hospital.
I woke up feeling really ill.
sick especially American English ill:
She’s been sick with the flu.
a sick child
Dan got sick on vacation.
not very well [not before noun] ill, but not seriously ill:
Sarah’s not very well – she has a throat infection.
unwell [not before noun] formal ill:
The singer had been unwell for some time.
Symptoms include fever, aching muscles, and feeling generally unwell.
poorly [not before noun] British English spoken ill:
Your grandmother’s been very poorly lately.
in a bad way [not before noun] very ill because of a serious injury or disease:
You’d better call an ambulance – she looks like she’s in a bad way.
be off sick British English, be out sick American English to be not at work because of an illness:
Two teachers were off sick yesterday.
under the weather (also off colour British English) [not before noun] informal slightly ill:
Sorry I haven’t called you – I’ve been a bit under the weather lately.
You look a bit off colour – are you sure you’re OK?
run down [not before noun] feeling slightly ill and tired all the time, for example because you have been working too hard, or not eating well:
Some people take extra vitamins if they are feeling run down.
in poor health unhealthy and often ill:
Chopin was already in poor health when he arrived on the island.
delicate weak and likely to become ill easily:
She was delicate and pale and frequently complained of headaches.
He had a delicate constitution and throughout his adult life suffered from various illnesses.
sickly a sickly child is often ill:
He was a sickly child and spent a lot of time at home on his own.
His younger daughter was sickly and died when she was young.

[TahlilGaran] English Thesaurus ▲