Freedom of movement to escort strongbox to the fore (4-7)
I believe the answer is:
safe-conduct
'freedom of movement' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?
'escort strongbox to the fore' is the wordplay.
'escort' becomes 'conduct' (I can't justify this - if you can you should give a lot more credence to this answer).
'strongbox' becomes 'safe' (safe is a kind of strongbox).
'to the fore' means one lot of letters go next to another.
'conduct' put after 'safe' is 'SAFE-CONDUCT'.
'to' is the link.
Can you help me to learn more?
(Other definitions for safe-conduct that I've seen before include "Travel permit affording protection" , "Permit to pass" .)