Went into decline and quietly died out (6)
I believe the answer is:
dipped
'went into decline' is the definition.
I can't tell whether this defines the answer.
'quietly died out' is the wordplay.
'quietly' becomes 'pp' (musical abbreviation for pianissimo).
'out' means one lot of letters goes inside another.
'pp' put within 'died' is 'DIPPED'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for dipped that I've seen before include "Dropped downward" , "Went down momentarily" , "Immersed momentarily" , "Lower beam of headlights" , "Like lowered headlights" .)