4 definitions
Existentialist ethics (n.) is ethics built on radical freedom and responsibility, without fixed human nature or external moral rules.
Existentialist ethics (n.) is responsibility that cannot be returned to a system.
Existentialist ethics (n.) works like painting: no one asks what picture an artist ought to paint, and nothing that should be done can be settled in advance, since both are invention.
Existentialist ethics (n.) has one answer for whoever asks what to do: you are free, therefore choose, that is, invent, for no general rule of morality can show the way.