-Is the phrase "Kill those who have no ghira (protective jealousy/sense of honor)" an authentic hadith, and what does it mean?

"Kill those who have no ghira (protective jealousy)" is not a Hadith, nor is its meaning Islamically sound. There is no mention in Islamic law of killing someone who lacks ghira or a dayyuth (one who permits immorality concerning his womenfolk). Killing such a person is an act of aggression against an inviolable soul, and it is forbidden. Praiseworthy ghira is a religious requirement, as stated in the Hadith: "Are you amazed at Sa'd's ghira? By Allah, I have more ghira than him."