Saw police getting upset over corporation (6)
I believe the answer is:
dictum
'saw' is the definition.
(thesaurus)
'police getting upset over corporation' is the wordplay.
'police' becomes 'cid'.
'getting upset' says the letters should be written in reverse.
'over' means one lot of letters go next to another.
'corporation' becomes 'tum' (I've seen this before).
'cid' written backwards gives 'dic'.
'dic'+'tum'='DICTUM'
(Other definitions for dictum that I've seen before include "Authoritative statement" , "Decree; maxim" , "Fiat" , "Formal statement - maxim" , "Statement - saying" .)