Asking too much from grocer having bananas (12)
I believe the answer is:
overcharging
'asking too much' is the definition.
Although both the answer and definition are present participle verbs, I can't see how they can define each other.
'grocer having bananas' is the wordplay.
'bananas' indicates anagramming the letters (bananas can informally mean crazy).
'grocer'+'having'='grocerhaving'
'grocerhaving' with letters rearranged gives 'OVERCHARGING'.
'from' is the link.
Can you help me to learn more?
(Another definition for overcharging that I've seen is " Ripping off".)