Ill and sick both mean not well, suffering from an illness; the difference is where they go. In British English ill usually comes after a verb (She's ill), and sick before a noun (a sick child, sick leave). In American English sick replaces ill almost everywhere, while for British speakers feel sick more often means “feel as if you are going to vomit”.
ill or sick — can you pick the right one?
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be/feel/fall + ill; seriously ill; sick + noun (sick child, sick leave, sick pay); feel sick (= nausea); be sick of + noun/-ing
- Anna is ill today, so we've moved the meeting to Thursday.
- I always feel sick on long coach journeys, so I sit at the front.
- Our neighbour looks after her sick father and rarely gets a day off.
What changed
First versionI stayed at home yesterday to look after my ill son.
RevisionI stayed at home yesterday to look after my sick son.
Before a noun, British speakers say sick: my sick son, sick children. Ill sounds natural after a verb: My son is ill. Learners who first met ill as the word for “not well” tend to put it before the noun too, and the phrase sounds awkward.
In British English be sick and feel sick are about nausea: I feel sick means “I think I'm going to vomit”, and He was sick in the car means “he vomited in the car”. To say you have fallen ill, I'm ill or I'm not feeling well is safer. And be sick of means “be fed up with”: I'm sick of this rain.
Your turn
After her operation, my colleague was on ___ leave for two weeks.
Show the answer
sick — Time off work because of illness is sick leave. It is a fixed phrase, and sick comes before leave. English has no phrase ill leave; ill usually comes after a verb: she was ill.
Write a short message to a colleague or teacher saying you are unwell. Use ill or sick, name the illness and say when you plan to be back.
Sorry, I'm ill with flu and won't be at the seminar today, but I hope to be back on Thursday.
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