Society getting soft still a western phenomenon (6)
I believe the answer is:
sunset
'phenomenon' is the definition.
(sunset is a kind of phenomenon)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for sunset that I've seen before include "When daylight fades" , "'The dying of the 18'" , "When the light begins to fall below the horizon" , "brilliant decline?" , "Twilight time" .)