cambridge gives this meaning of ill
not feeling well, or suffering from a disease
and this meaning of sick
physically or mentally ill; not well or healthy
So, when someone, say Alice, has got a cold, which one of following is more appropriate?
Alice is sick
Alice feels ill
or some other expression?
When I say Alice is sick (or some other more appropriate word), I would like to have my audience realize that Alice may have got a cold, other than "Alice is in trouble, Alice is insane".