Fence becoming more insignificant (6)
I believe the answer is:
paling
'fence' is the definition.
(I know that paling is a type of fence)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for paling that I've seen before include "Fence made of stakes" , "is becoming whiter" , "Fence post - turning white" , "Barrier of stakes" .)