Pop or otherwise, music right for the occasion (9)
I believe the answer is:
opportune
'right for the occasion' is the definition.
I can't judge whether this definition defines the answer.
'pop or otherwise music' is the wordplay.
'otherwise' indicates anagramming the letters.
'music' becomes 'tune' (tune is a kind of music).
'pop'+'or'='popor'
'popor' is an anagram of 'oppor'.
'oppor'+'tune'='OPPORTUNE'
Can you help me to learn more?
(Other definitions for opportune that I've seen before include "Timely and convenient" , "Appropriate" , "Occurring at a fitting time" , "Timely, advantageous moment" , "fit" .)