Lie about Conservative row (7)
I believe the answer is:
recline
'lie' is the definition.
(I know that recline is a kind of lie)
'about conservative row' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'conservative' becomes 'C' (UK political abbreviation).
'row' becomes 'line' (as in a row of things).
're'+'c'+'line'='RECLINE'
(Other definitions for recline that I've seen before include "sit back ..." , "Lie on one's back" , "Lie back and take it easy" , "Lean back, relax" , "Lie back and relax" .)