Reprimand innocent master discovered (8)
I believe the answer is:
lambaste
'reprimand' is the definition.
(I know that reprimand can be written as lambaste)
'innocent master discovered' is the wordplay.
'innocent' becomes 'lamb' (I've seen this in another clue).
'discovered' indicates the central letters (dis-covered - outer letters removed).
The central letters of 'master' are 'aste'.
'lamb'+'aste'='LAMBASTE'
(Other definitions for lambaste that I've seen before include "Censure severely or angrily" , "Berate severely" , "Batter - male bats (anag)" , "Harshly criticise" , "hit in a way that's hard to beat?" .)