Unprincipled (6)
'unprincipled' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for amoral that I've seen before include "Blind to right and wrong" , "Not knowing right or wrong" , "Without sense of right and wrong" , "Ignoring what's right and wrong" , "Unconcerned about what's right or wrong" .)
'unprincipled' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for immoral that I've seen before include "Promiscuous" , "Without a sense of right and wrong" , "Violating accepted principles of right and wrong" , "Lacking a sense of right and wrong" , "Wicked" .)