Crossword Genius

Good when the glass is going up (6)

Ross

I believe the answer is:

health

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'good' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

I don't understand the remainder of the clue.

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(Other definitions for health that I've seen before include "State of well-being" , "Fettle -- condition" , "Freedom from illness" , "Fit condition" , "It's said to be more than wealth" .)

I've seen this clue in The Globe and Mail.
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