Authoritarian laid Riot Act out (11)
I believe the answer is:
dictatorial
'authoritarian' is the definition.
(I know that authoritarian can be written as dictatorial)
'laid riot act out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'laid'+'riot'+'act'='laidriotact'
'laidriotact' with letters rearranged gives 'DICTATORIAL'.
(Other definitions for dictatorial that I've seen before include "Overbearing" , "Given to telling others what to do" , "Autocratic" , "tyrannical" .)