Ethics is the Greek word for the science of morals. Ethos is the disposition or mindset of a culture.
From a compound of kakos and ethos; bad character, i.e. (specially) mischievousness — malignity.
I have used some examples of how to measure the ethos of a culture. One is how it treats the most vulnerable. Another is how it buries it’s dead. There are reasons to use those as measurements of an ethic that we don’t need to get into right now, but their is an ability to judge a moral character very guickly unless one is morally tone deaf themselves. That is the point of Romans 1 – every human being apart from God’s intervention has a malignant character. It is kako.
This may seem needlessly childish but kaka (kako), is almost universally understood as a childish word for poo or something nasty. Humans apart from God’s intervention have nasty morals and dispositions.