as a noun, 'ill' refers to misfortune or difficulty.
No ill will come from speaking the truth.
She bears him no ill.
The ills of society are many and varied.
when used as a noun, 'ill' is often paired with words like 'will' (ill will) or used in plural form to describe multiple problems or difficulties (ills).
as an adjective, 'ill' describes a state of poor health or a negative quality or condition.
'ill' can describe someone who is not in good health. It can also describe unfavorable conditions or qualities.
He has been ill for a week now.
The ill effects of smoking are well-documented.
There's an ill wind blowing from the north.
'ill' and 'sick' can often be used interchangeably, but in some contexts, one might be more appropriate than the other. For instance, in British English, 'ill' is more commonly used to refer to health, while 'sick' might refer to vomiting.
Avoid confusing 'ill' with 'I'll', a contraction of 'I will'.
as an adverb, 'ill' modifies verbs, adjectives, or other adverbs, indicating in a poor or unsatisfactory manner.
it can be used to describe an action done poorly or wrongly.
The project was ill conceived from the start.
He spoke ill of his colleagues.
The message was ill received by the community.
'ill' as an adverb is often followed by another adjective or past participle.