When mum's out, do wrong, I see, just a little (7)
I believe the answer is:
modicum
'just a little' is the definition.
(I've seen this before)
'when mum's out' is the wordplay.
'when' becomes 'odic' (I can't explain this - if you can you should give a lot more credence to this answer).
'out' means one lot of letters goes inside another.
'odic' placed within 'mum' is 'MODICUM'.
'do wrong i see' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for modicum that I've seen before include "Mum, I cod about a small amount" , "A small amount as of drink" , "suggestion" , "Token amount" , "I cod Mum into providing a small quantity" .)