Earmark made by telephone receiver (4-5)
I believe the answer is:
ring-fence
'earmark' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'by telephone receiver' is the wordplay.
'by' is a charade indicator (letters next to each other).
'telephone' becomes 'ring' (synonyms).
'receiver' becomes 'fence' (I've seen this before).
'ring' next to 'fence' is 'RING-FENCE'.
'made' acts as a link.
Can you help me to learn more?
(Other definitions for ring-fence that I've seen before include "Enclose with a barrier" , "estate security" , "Barrier completely enclosing an area of land" , "Complete barrier" , "Allocate (funds) to one purpose" .)