Definitely not the very smallest (5,2,3)
I believe the answer is:
least of all
'definitely not the very' is the definition.
I can't judge whether this defines the answer.
'smallest' is the wordplay.
I cannot really understand how this works, but
'smallest' could be 'least' (synonyms) and 'least' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
I've seen this clue in the Evening Standard.
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