Smallest scale as time excessive (5)

I believe the answer is:

least

I'm a little stuck... Click here to teach me more about this clue!

'smallest' is the definition.
(synonyms)

'scale as time excessive' is the wordplay.
'LEAST' is hidden in amongst the letters.
However, I'm uncertain how this is indicated.

Can you help me to learn more?

(Other definitions for least that I've seen before include "Smallest, being stale" , "Opposite of most" , "Lowest or smallest" , "Smallest in amount or degree" , "Steal (anag)" .)

I've seen this clue in the Sydney Morning Herald.

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