Ring roads tend to fit long-term directive (8,5)
I believe the answer is:
standing order
'long-term directive' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'ring roads tend to fit' is the wordplay.
'to fit' indicates an anagram (letters fitted or arranged in a different way).
'ring'+'roads'+'tend'='ringroadstend'
'ringroadstend' is an anagram of 'STANDING ORDER'.
Can you help me to learn more?
(Other definitions for standing order that I've seen before include "Arrangement made with bank to pay" , "Instruction to bank for payment at regular intervals" , "Regular way to pay" , "rise!" , "Instruction for bank to make regular payments" .)