wicked and immoral
nefarious - wicked
The word ‘nefarious’ suggests something deliberate, planned, and highly reprehensible. For that reason, you often see it used with words like ‘plot’, ‘scheme’, ‘activities’, etc. It is more frequently used in a professional context, particularly in relation to corrupt practices in business or government.
The military operation was part of a nefarious plot to overthrow the democratically elected government.
That businessman has been involved in some nefarious activities. I wouldn’t deal with him if I were you.
Our data leaks were due to ineptitude rather than nefariousness, so no criminal charges will be brought.