Backing for yellow vests securing popular gains (4)
I believe the answer is:
wins
'gains' is the definition.
(win is a kind of gain)
'backing for yellow vests securing popular' is the wordplay.
'backing for' is a reversal indicator.
'yellow vests' becomes 'sw' (I can't justify this - if you can you should give a lot more credence to this answer).
'securing' indicates putting letters inside.
'popular' becomes 'in'.
'sw' reversed gives 'ws'.
'ws' placed around 'in' is 'WINS'.
Can you help me to learn more?
(Other definitions for wins that I've seen before include "Finishes in first place" , "Victories" , "Triumphs" .)