Orders acid test rearranged (8)
I believe the answer is:
dictates
'orders' is the definition.
('dictate' can be a synonym of 'order')
'acid test rearranged' is the wordplay.
'rearranged' indicates an anagram.
'acid'+'test'='acidtest'
'acidtest' is an anagram of 'DICTATES'.
(Other definitions for dictates that I've seen before include "Orders" , "Gives imperative command in acid test" .)