From Dior, dainty frock (6)

I believe the answer is:

ordain

'frock' is the definition.
(thesaurus)

'from dior dainty' is the wordplay.
'from' says the answer is hidden in the clue.
'ORDAIN' is hidden in the letters of 'dior dainty'.

(Other definitions for ordain that I've seen before include "Lay down (law)" , "Destine" , "Rule" , "Install as priest" , "Decree or appoint to priesthood" .)

I've seen this clue in The Telegraph.

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