Order international court to stop appointment (7)
I believe the answer is:
dictate
'order' is the definition.
(synonyms)
'international court to stop appointment' is the wordplay.
'international' becomes 'i' (abbreviation eg in IMF).
'court' becomes 'ct' (abbreviation used in road names).
'to stop' means one lot of letters goes inside another (inserted letters plug or stop a gap).
'appointment' becomes 'date' (synonyms).
'i'+'ct'='ict'
'ict' put within 'date' is 'DICTATE'.
(Other definitions for dictate that I've seen before include "speak slowly" , "say" , "Give orders like Stalin" , "Determine; read out to be taken down" , "Order; determine" .)