sick as a dog
Meaning
Very ill, often with nausea or vomiting; extremely sick.
Origin
Recorded from at least the 18th–19th centuries; it uses “dog” as an intensifier for misery/illness, likely influenced by the idea of dogs becoming visibly unwell (vomiting) and the older phrase “dog-sick.”
Notes
Informal and emphatic; often suggests nausea/vomiting. Avoid in formal contexts—use “very ill” instead.
Examples
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I missed the meeting because I was sick as a dog all day.
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After eating that street food, he was sick as a dog and stayed in bed.
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She sounded sick as a dog on the phone, so I told her to rest.
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I felt sick as a dog during the flight and couldn’t even look at the food.
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If you’re still sick as a dog tomorrow, you should see a doctor.
Grammar & Usage Notes
Fixed simile pattern: “as sick as a dog.” Usually used with linking verbs: “be/feel/look sick as a dog.” Article is fixed (“a dog”). Can be intensified (“really sick as a dog”), but wording is mostly fixed.
Synonyms
- very ill
- sick as hell
- sick as a parrot
- under the weather (milder)
Antonyms
- well
- fine
- healthy
- fit as a fiddle