Not going up on almost all acoustic (5)
I believe the answer is:
tonal
'acoustic' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
'not going up on almost all' is the wordplay.
'going up' shows that the letters should be reversed in order.
'on' is a charade indicator (letters next to each other).
'almost' means to remove the last letter (most of the word but not all of it).
'not' back-to-front is 'ton'.
'all' with its final letter taken off is 'al'.
'ton'+'al'='TONAL'
Can you help me to learn more?
(Other definitions for tonal that I've seen before include "sound character" , "Relating to conventional keys and harmonies" , "Written in conventional keys and harmony" , "of pitch" , "of sound quality" .)