More familiar Conservative defeated opponent (6)
I believe the answer is:
closer
'more famiiar' is the definition.
I can't tell whether this definition defines the answer.
'conservative defeated opponent' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'defeated opponent' becomes 'loser'.
'c'+'loser'='CLOSER'
(Other definitions for closer that I've seen before include "Cresol (anag.)" , "Comparatively near" , "more reticent" , "not so remote" , "Stuffier" .)