Former lover taking hard drinks expires (7)
I believe the answer is:
exhales
'expires' is the definition.
('exhale' can be a synonym of 'expire')
'former lover taking hard drinks' is the wordplay.
'former lover' becomes 'ex'.
'taking' means one lot of letters go next to another.
'hard' becomes 'h'.
'drinks' becomes 'ales' (I've seen this before).
'ex'+'h'+'ales'='EXHALES'
(Other definitions for exhales that I've seen before include "Breathes out" , "expires" .)