Phone receiver put to specific use (4-5)
I believe the answer is:
ring-fence
'to specific use' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'phone receiver' is the wordplay.
'phone' becomes 'ring' (to ring on the phone).
'receiver' becomes 'fence' (I've seen this before).
'ring'+'fence'='RING-FENCE'
'put' acts as a link.
Can you help me to learn more?
(Other definitions for ring-fence that I've seen before include "Protect or guarantee - with circular hedge?" , "Allocate (funds) to one purpose" , "Enclose with a barrier" , "Complete barrier" , "estate security" .)