Diseases or conditions of poor health; times when a person is sick or not feeling well.
From 'illness' (ill- + -ness), where 'ill' comes from Old Norse 'illr' (bad or evil). The suffix '-ness' turns adjectives into nouns expressing a state or condition.
Interestingly, 'illness' and 'sickness' mean similar things, but 'sickness' often refers to nausea/vomiting specifically, while 'illness' is the broader term—language developed different words because we needed precision about different health problems.
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