Not taking drink out — can found inside (9)
I believe the answer is:
abstinent
'not taking drink' is the definition.
(I've seen this before)
'out can found inside' is the wordplay.
'out' becomes 'absent' ('absent' can be similar in meaning to 'out').
'can' becomes 'tin' ('tin' can be a synonym of 'can').
'found inside' is an insertion indicator.
'absent' enclosing 'tin' is 'ABSTINENT'.
(Other definitions for abstinent that I've seen before include "nowhere near the drink" , "self-restraint" , "Forsaking alcohol" , "Self-denying" , "Avoiding alcohol" .)