From Wikipedia: "Egyptians often refer to Cairo as Maṣr (IPA: [mɑsˤɾ]; Egyptian Arabic: مَصر), the Egyptian Arabic name for Egypt itself, emphasizing the city's importance for the country. Its official name al-Qāhirah (Arabic: القاهرة) means "the Vanquisher" or "the Conqueror", supposedly due to the fact that the planet Mars, an-Najm al-Qāhir (Arabic: النجم القاهر, "the Conquering Star"), was rising at the time when the city was founded...".
Multiple other sources translate Cairo (or Qahirah) as "powerful", "overpowering", "victorious".
Multiple other sources translate Cairo (or Qahirah) as "powerful", "overpowering", "victorious".
So it's not really Arabic for "Mars".