Recording socialist who got thinner (7)
I believe the answer is:
tapered
'got thinner' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Maybe there's an association between them I don't understand?
'recording socialist' is the wordplay.
'recording' becomes 'tape' (tape recording is a kind of recording).
'socialist' becomes 'red' (socialism is often associated with the colour red).
'tape'+'red'='TAPERED'
'who' acts as a link.
Can you help me to learn more?
(Other definitions for tapered that I've seen before include "Narrowed to a point" , "Narrowed by red tape" , "With thickness reduced towards an end" , "Gradually narrowing" , "Predate (anag)" .)