With no scruples, nose goes over line (6)
I believe the answer is:
amoral
'with no scruples' is the definition.
'nose goes over line' is the wordplay.
'nose' becomes 'aroma' (I've seen this before**).
'goes over' says the letters should be written in reverse (I've seen 'go over' mean this).
'line' becomes 'l'.
'aroma' back-to-front is 'amora'.
'amora'+'l'='AMORAL'
(Other definitions for amoral that I've seen before include "unconcerned about ethics" , "outrageous!" , "Without an ethical code" , "Unconcerned about what's right or wrong" , "Unconcerned with correctness" .)