Individual takes most of what we have here surreptitiously (2,3,3)
I believe the answer is:
on the sly
'surreptitiously' is the definition.
(I've seen this before)
'individual takes most of what we have here' is the wordplay.
'individual' becomes 'only' (I can't explain this - if you can you should believe this answer much more).
'takes' means one lot of letters goes inside another.
'most of' means to remove the last letter.
'what we have here' becomes 'these' (I've seen this in another clue).
'these' with its final letter taken away is 'thes'.
'only' enclosing 'thes' is 'ON THE SLY'.
Can you help me to learn more?
(Other definitions for on the sly that I've seen before include "Under the table" , "Secretly or furtively" , "Surreptitiously" , "under cover" , "in private" .)