For me, ethics are something deeply internal and individual. I think they are something quite fundamental, formed at a very young age, and best imparted by parents and older role models.
For some, even those who are taught well, the ethical compass goes haywire later in life. Greed and self interest are the biggest enemies of ethics. It's mainly for money but it can also be for sex or power.
My experience with the phrase is that it describes one's level of commitment to a task/employer/course of study. Ability to go the extra mile, stay the course, persistence to achieve quality, finding resources when stuck, own the problems that arise, etc. Punctuality and showing up fall in there, too.
I try to learn the mission statement and vision of the organization that I am working for before I commit my time, my passion, and my energy to it. If I believe in the mission/vision statements and I am reasonably sure that the supervisors abide by most of it, I will give my time, my extra hours, and my positive attitude to the agency. I need to be able to transmit that mission even on the worst days and to remember that you must balance your love for work with your love for health and take time to reflect, relax, and play.
Failure to act ethically is at once a betrayal of another person or of a system/institution. Ultimately I believe it is even a type of self-betrayal of the individual who behaves unethically.
In one way or another, those who act that way will pay an individual price. The price may be one of emotional turmoil created by a complicated life or something as simple as the stress of being afraid of discovery. Nothing in this life comes for free. Except the truly priceless, good things (like happiness, love and trust)!