The phrase “εκ των ων ουκ ανευ” is an ancient phrase that has survived in modern Greek. It means “irreplaceable”, “absolutely necessary”.
It is a formal phrase and we do not use it when we speak in our everyday life. We may hear it, for example, in the speech of a politician or a scientist.
Example: “Ο σεβασμός στα ανθρώπινα δικαιώματα είναι εκ των ων ουκ ανευ σ' ένα πολιτισμένο κράτος ”. = Τhe respect in human rights is absolutely necessary in a civilized country.