A good but quiet light (4)

I believe the answer is:

glow

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'light' is the definition.
(glow is a kind of light)

'a good but quiet' is the wordplay.
'a good' becomes 'g' (abbreviation).
'but quiet' becomes 'low' (I am not sure about the 'but' bit.**).
'g'+'low'='GLOW'

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(Other definitions for glow that I've seen before include "Redness of the cheeks" , "Brightness" , "Emit light and heat without flame" , "Gleam" , "Emanate light" .)

I've seen this clue in the Evening Standard.

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