Zaynab Khan is an old Arabic insult stemming from the word عنيف which translates to Aggressive.
The insult originated from
people mocking one of Genghis khan's Wives which was highly aggressive, ordering the death of hundreds just to satisfy her
boredomA person would typically call someone else Zaynab Khan or just Zaynab / Khan to emphasise there barbaric behaviour or there unsensitive attitudes towards less fortunate
people.
The word is rarely used now but is more frequently used by older generations