Short fool, not heavy, appearing when it's dusk (8)

I believe the answer is:

twilight

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'it's dusk' is the definition.
(synonyms)

'short fool not heavy' is the wordplay.
'short' means to remove the last letter.
'fool' becomes 'twit' (both can mean a stupid person).
'not heavy' becomes 'light' ('light' is the opposite to 'heavy').
'twit' with its last letter removed is 'twi'.
'twi'+'light'='TWILIGHT'

'appearing when' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.

Can you help me to learn more?

(Other definitions for twilight that I've seen before include "nightfall" , "Glow after sunset" , "Condition of decline" , "The Remains of the Day?" , "Vampire book" .)

I've seen this clue in The Daily Express.

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