Viz not usual standard fare (5)

I believe the answer is:

scoff

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'fare' is the definition.
(I've seen this before)

'viz not usual standard' is the wordplay.
'viz' becomes 'sc'.
'not usual standard' becomes 'off' (I can't justify this - if you can you should believe this answer much more).
'sc'+'off'='SCOFF'

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(Other definitions for scoff that I've seen before include "Furiously swallow" , "Greedily consume" , "Speak derisively" , "Speak scornfully; eat" , "Deride - guzzle" .)

I've seen this clue in The Telegraph.

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