Something afoot in the back of the car (4)
I believe the answer is:
boot
'car' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'something afoot in the back of' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
The remaining letters 'bo' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'the' is the link.
Can you help me to learn more?
(Other definitions for boot that I've seen before include "They call it a trunk in the US" , "may be packed for a journey" , "Dismiss" , "Hard kick (colloq.)" , "eg Wellington" .)