Not many working early to late, say (7)

I believe the answer is:

antonym

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'early to late say' is the definition.
I can't tell whether this definition defines the answer.

'not many working' is the wordplay.
'working' indicates anagramming the letters.
'not'+'many'='notmany'
'notmany' anagrammed gives 'ANTONYM'.

Can you help me to learn more?

(Other definitions for antonym that I've seen before include "as host is for guest, eg" , "that means reverse" , "Opposite-meaning word" , "opposing description" , "As 'happy' is to 'sad' or 'long' to 'short'" .)

I've seen this clue in The Guardian.

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