Man in pub backing recovery (5)
I believe the answer is:
rehab
'recovery' is the definition.
(where a drug addict might recover)
'man in pub backing' is the wordplay.
'man' becomes 'he' (pronoun for a man).
'in' indicates putting letters inside.
'pub' becomes 'bar' (both are drinking establishments).
'backing' says the letters should be written in reverse.
'he' inserted into 'bar' is 'baher'.
'baher' in reverse letter order is 'REHAB'.
(Other definitions for rehab that I've seen before include "Restoration to health after, eg, addiction (colloq.)" , "Training and therapy after drug abuse" , "A herb (anag.)" , "Treatment for alcohol or drug dependence" , "Treatment for alcohol abuse" .)