In a manner that is healthful and promotes wellbeing.
From 'healthsome' (health + -some) plus '-ly', creating an adverbial form that would describe actions or states in a health-promoting way.
This word is so archaic and rare that it barely appears in modern English, yet it perfectly demonstrates how productive English suffixes are—you could theoretically stack '-some' and '-ly' on almost any noun, even if no one actually does!
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