A month ultimately for key conclusion: none softening (11)
I believe the answer is:
decrescendo
'softening' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'a month ultimately for key conclusion none' is the wordplay.
I cannot quite understand how this works, but
'month' could be 'dec' (abbreviation for December) and 'dec' is found in the answer.
'key' could be 'd' (musical key) and 'd' is found within the answer.
'none' could be 'no' and 'no' is found in the leftover letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for decrescendo that I've seen before include "Decrease in loudness (music)" , "With decreasing loudness (mus.)" , "decline" , "Slow reduction in sound intensity" , "Reduction in sound volume" .)