Agitatedly stir up a pedant (6)
I believe the answer is:
purist
'a pedant' is the definition.
(purist is a kind of pedant)
'agitatedly stir up' is the wordplay.
'agitatedly' is an anagram indicator (I've seen this in other clues).
'stir'+'up'='stirup'
'stirup' with letters rearranged gives 'PURIST'.
(Other definitions for purist that I've seen before include "scrupulous" , "Pedantic type" , "Fastidious person" , "One who insists on precision and correctness" , "Stir up (anag) - pedant" .)