Retiring American politician in the car (4)
I believe the answer is:
sump
'the car' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'retiring american politician' is the wordplay.
'retiring' says the letters should be written backwards.
'american' becomes 'us' (abbreviation for United States).
'politician' becomes 'MP' (Member of Parliament).
'us' backwards is 'su'.
'su'+'mp'='SUMP'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for sump that I've seen before include "Oil store" , "Lubrication reservoir" , "Hole collecting water for pump" , "Pit receiving drainage" , "Into which liquids drain" .)