Official order or commission to do something (7)
I believe the answer is:
mandate
'official order or commission to do something' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mandate that I've seen before include "Authority given to perform certain task" , "Give authority to" , "Social appointment for male - or authority given" , "Make compulsory" , "Authority to act" .)