Improvised on the radio in break (4)
I believe the answer is:
rift
'break' is the definition.
(rift can mean a break or opening)
'improvised on the radio' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
The remaining letters 'rif' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'in' is the link.
Can you help me to learn more?
(Other definitions for rift that I've seen before include "Serious falling out" , "Breach, rupture" , "Schism (in the lute?)" , "Breach; crack" , "Lack of harmony" .)