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sickness vs. illness

[sik-nis] / ˈsɪk nɪs /

noun

  1. a particular disease or malady.

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

  3. nausea; queasiness.

[il-nis] / ˈɪl nɪs /

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.