Fell over close to buffet car (5)
I believe the answer is:
motor
'car' is the definition.
(thesaurus)
'fell over close to buffet' is the wordplay.
'fell' becomes 'moor' (I've seen this before).
'over' indicates putting letters inside.
'close to' says to take the final letters (the close/ending of).
The final letter of 'buffet' is 't'.
'moor' placed around 't' is 'MOTOR'.
(Other definitions for motor that I've seen before include "Car; travel quickly" , "Car (informal)" , "Move quickly" , "Internal combustion engine" , "Travel by car, engine" .)