Barrier to communication worried court in Iran (4,7)
I believe the answer is:
iron curtain
'barrier' is the definition.
(iron curtain is a kind of barrier)
'worried court in iran' is the wordplay.
'worried' is an anagram indicator (worry can mean to interfere with or disturb).
'court'+'in'+'iran'='courtiniran'
'courtiniran' is an anagram of 'IRON CURTAIN'.
'to communication' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for iron curtain that I've seen before include "term famously used by Churchill" , "What divided European sides" , "Former dividing line across Europe" , "Old barrier between East & West Europe" , "former division in Europe" .)