ill and sick

Ill and sick are both used to mean ‘unwell’. (In American English ill is less usual except in a formal style.)

• George didn’t come in last week because he was ill/sick.

Ill is not very common before a noun.

• I’m looking after my sick mother. (More normal than … my ill mother.)

Be sick can meant ‘vomit’ (= bring food up from the stomach) in British English.

• I was sick three times in the night.