Waste a lot, getting Susie upset (6)
I believe the answer is:
misuse
'waste' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'a lot getting susie upset' is the wordplay.
'a lot' becomes 'm' ().
'getting' is a charade indicator (letters next to each other).
'upset' indicates an anagram.
'susie' with letters rearranged gives 'isuse'.
'm'+'isuse'='MISUSE'
Can you help me to learn more?
(Other definitions for misuse that I've seen before include "harm" , "exploitation" , "Maltreat" , "Application to a bad purpose" , "bad treatment" .)