Summary on Scotsman, a purist (9)

I believe the answer is:

precisian

'a purist' is the definition.
(thesaurus)

'summary on scotsman' is the wordplay.
'summary' becomes 'precis' (precis is a kind of summary).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'scotsman' becomes 'ian' (common Scottish name).
'precis'+'ian'='PRECISIAN'

(Another definition for precisian that I've seen is " Stickler for rules".)

I've seen this clue in The Telegraph.

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