Upon reflection, it looks bright (4)

I believe the answer is:

moon

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'it looks bright' is the definition.
The definition suggests a singular noun which matches the answer.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for moon that I've seen before include "High light" , "Night light" , "Daydream - Europa of Jupiter, say" , "Happy to be over this" , "low point" .)

I've seen this clue in the Evening Standard.

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