Ill (adjective)

1. Not feeling physically well; unwell.
2. Having an illness.
3. Having a harmful or negative effect.
4. Not in a satisfactory state or condition; not well.

Origin:

Middle english ille, from old english yfel, of germanic origin; related to dutch and german übel, also to evil.

Examples:

1. She has been ill for several days now.
2. He was taken to the hospital with a serious illness.
3. The pollution is having an ill effect on the environment.
4. The company is doing ill and may have to lay off workers.
5. The news of her death came as an ill shock.