Order ready for publication, maintaining copyright principally (5)
I believe the answer is:
edict
'order' is the definition.
(synonyms)
'ready for publication maintaining copyright principally' is the wordplay.
'ready for publication' becomes 'edit' (I've seen this before).
'maintaining' is an insertion indicator.
'principally' suggests taking the first letters.
The initial letter of 'copyright' is 'c'.
'edit' placed around 'c' is 'EDICT'.
(Other definitions for edict that I've seen before include "Order issued by an authority" , "Regulation" , "Decree, fiat" , "Formal proclamation" , "Legally binding command" .)