Left one politician with walking difficulty (4)
I believe the answer is:
limp
'walking difficulty' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'left one politician' is the wordplay.
'left' becomes 'l' (common abbreviation).
'one' becomes 'i' (roman numeral).
'politician' becomes 'mp' (Member of Parliament).
'l'+'i'+'mp'='LIMP'
'with' is the link.
Can you help me to learn more?
(Other definitions for limp that I've seen before include "Lacking stiffness" , "Wanting stiffness" , "Saggy and drooping" , "Hobble, being slack" , "Flabby - halt" .)