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This word seems to have its origins in the word "whole" or "wholeness" since it is an abstract word that refers to the physical state of a body, which is usually human. In other words we usually associate it with the physical state of a human or living being. People are said to be "in good health" or "enjoying good health". On the other side they could also be "suffering from poor health" or be "in poor health". It isn't until we get to the adjective "healthy" that we are talking about being "in good health". Athletes and sportsmen and women are usually "healthy".
We can also use the adjective to describe not only a physical attribute but also a moral one. You can have a "healthy attitude towards religion or sex", which means that you are objective in the views that you hold on those topics.
At the same time we can use the adjective "healthy" for states or conditions that are not directly to do with living things. We speak of the economy of a country being "healthy", which means that the country does not have huge debts.
When we raise a glass of drink to someone, we address the other person with the words: "Your health". We are in fact wishing that they are in "good health". And of course your personal health is a very important matter. A very common comment passed between people when they are talking about their money problems or their job prospects is "As long as you've got your health". This is a way of cheering themselves up by realising that whatever their problems, at least they don't have any problems with their "health".
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