origin Arabic English.
Is a mispronunciation and corruption of the word 'cousin' by those Middle Eastern decent. By referring to a person as 'kez' or 'cousin', the speaker is implying a title and a deal of affection or respect for the person.
Leb2: oath, kez!
'That girl done a kez on me man'
'Leave that girl, shes being a kez'
'Leave her shes doing a kez'