How sanctimonious setter might be compared to you! (6-4-4)

I believe the answer is:

holier-than-thou

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'how sanctimonious' is the definition.
'holier-than-thou' can be an answer for 'sanctimonious' (synonyms). I am not certain of the 'how' bit.

'setter might be compared to you' is the wordplay.
'setter might be' becomes 'holier' (I can't explain this - if you can you should believe this answer much more).
'compared to' becomes 'than' (I've seen this before).
'you' becomes 'thou' (historical second person pronoun).
'holier'+'than'+'thou'='HOLIER-THAN-THOU'

Can you help me to learn more?

(Other definitions for holier-than-thou that I've seen before include "Self-righteous" , "Sanctimonious" .)

I've seen this clue in The Telegraph.

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