On return, deduces pounds must go inside, hidden (8)
I believe the answer is:
secluded
'hidden' is the definition.
(thesaurus)
'on return deduces pounds must go inside' is the wordplay.
'on return' is a reversal indicator.
'pounds' becomes 'L' (L can represent the monetary pound).
'must go inside' indicates putting letters inside.
'deduces' going around 'l' is 'dedulces'.
'dedulces' reversed gives 'SECLUDED'.
(Other definitions for secluded that I've seen before include "Sheltered and private" , "Out of sight - away from society" , "Screened or sheltered from view" , "Private - withdrawn" , "Out of the way" .)