sickness vs. illness

sickness

noun

  1. a particular disease or malady.

  2. the state or an instance of being sick; illness.

  3. nausea; queasiness.

illness

noun

  1. poor health; sickness.

    He grew up in an environment known for poverty, illness, and little opportunity for education.

  2. a specific sickness or disease, or an instance of such.

    Please be as accurate as possible in listing your childhood illnesses.

    Synonyms: infirmity, affliction, ailment

  3. Obsolete.,  wickedness.