Engine sound in Rolls-Royce after turning up (4)
I believe the answer is:
purr
'engine sound' is the definition.
(I've seen this in another clue)
'rolls-royce after turning up' is the wordplay.
'rolls royce' becomes 'rr' (short for Rolls Royce).
'after' says to put letters next to each other.
'turning' says the letters should be written in reverse.
'up' in reverse letter order is 'pu'.
'rr' put after 'pu' is 'PURR'.
'in' acts as a link.
(Other definitions for purr that I've seen before include "Sound of feline content" , "Sound of contentment" , "content? I might" , "Sound of a contented feline" , "Make low, contented sound" .)