as sick as a dog
Meaning
Extremely ill, often with nausea or vomiting; very unwell.
Origin
Recorded from the 1700s; it draws on the old association of dogs with vomiting or looking wretched when ill, so “like a dog” intensifies the degree of sickness.
Notes
Informal intensifier meaning “very ill,” often implying nausea/vomiting. Fine in conversation; in formal settings use “very ill” or “seriously unwell.”
Examples
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After that roadside seafood, I was as sick as a dog all night.
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She caught the flu and felt as sick as a dog for three days.
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I tried to go to work, but I was as sick as a dog and had to turn back.
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He looked as sick as a dog after the boat hit rough water.
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If you eat that undercooked chicken, you’ll be as sick as a dog tomorrow.
Grammar & Usage Notes
Fixed simile pattern: “as sick as a dog.” You can change tense around it (e.g., “was as sick as a dog”), but the core phrase is usually unchanged.
Synonyms
- very ill
- really sick
- sick as a parrot
- sick as a pig
Antonyms
- as fit as a fiddle
- in good health
- well