Not much left in rubbish mostly (6)
I believe the answer is:
little
'not' is the definition.
Both the answer and definition are adverbs. Maybe they are linked in a way I don't understand?
'much left in rubbish mostly' is the wordplay.
'much left' becomes 'l' (common abbreviation. I am not sure about the 'much' bit.).
'in' indicates putting letters inside.
'rubbish' becomes 'litter' (litter is a kind of rubbish).
'mostly' means to remove the last letter.
'litter' with its last letter taken away is 'litte'.
'l' put inside 'litte' is 'LITTLE'.
Can you help me to learn more?
(Other definitions for little that I've seen before include "Book by Dickens" , "'...... pitchers have large ears'" , "Novel heroine born in the Marshalsea" , "(Heroine of) Dickens novel" , "Small or minute" .)