‘ill’ vs ‘sick’

What is the difference between ‘ill’ and ‘sick’?*

Many students often ask what the difference between using ‘ill’ and ‘sick’ is. Some teachers will tell their students that the two words have virtually the same meaning and while that is true, there are some small differences you should be aware of.

While the words ‘ill’ and ‘sick’ both refer to someone or something being unwell, ill tends to be more formal and be used less in American English than sick. Additionally, it is not so common to use ‘ill’ infront of a noun. For example, instead of saying, “I’m looking after my sick mother”, we tend to prefer to say, “I’m looking after my ill mother”.

I have noted that in Australia and New Zealand (and I am sure other parts of the words as well) sick can also refer to vomitting.For example: I was sick 3 times last night.

* Explanations and examples drawn from ” Swan, M.2005. Practical English Usage. (3rd edition). Oxford University Press.