Deal a heavy blow to Conservative boor (5)
I believe the answer is:
clout
'deal a heavy blow' is the definition.
'clout' can be an answer for 'deal' (thesaurus). I'm not sure about the 'a heavy blow' bit.
'conservative boor' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'boor' becomes 'lout' (I've seen this before).
'c'+'lout'='CLOUT'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for clout that I've seen before include "Ne'er cast a ... till May be out, it's said" , "Influence; heavy blow" , "strike" , "Old-fashioned garment" , "Lay one on" .)