Rotter rough with a cold in luxury motor (8)
I believe the answer is:
cadillac
'luxury motor' is the definition.
The definition suggests a singular noun which matches the answer.
'rotter rough with a cold' is the wordplay.
'rotter' becomes 'cad' (I've seen this in another clue).
'rough' becomes 'ill'.
'with' means one lot of letters go next to another.
'cold' becomes 'c' (eg on taps).
'cad'+'ill'+'a'+'c'='CADILLAC'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for cadillac that I've seen before include "Car maker" , "Make an acid call for the US car" , "Make acid call to car company" , "American brand of luxury car" , "Luxury US automobile" .)