Today (at sundown, to be precise) is also Yom Kippur, the Day of Atonement, the holiest day of the year for Jews. I bring this up first to wish any Jewish readers an easy fast, but also because linguistically it’s a quick and easy way to highlight the common Semitic roots of both Arabic and Hebrew. “Yom Kippur” (which is, I hope, יום כיפור in Hebrew, because if it’s not then I’m afraid I just offended somebody) literally translates into Arabic as يوم غفور (yawm ghafūr). “Yawm,” or “yom” means “day,” obviously, and there’s some common Semitic root for the idea of “forgiveness” that developed into GH-F-R in Arabic and K-P-R in Hebrew. The relationship between “f” and “p” is so close that there’s an actual linguistic law about it, albeit one developed in the Indo-European context, and “gh” and “k” are similar enough sounds as well.
I should note that يوم غفور is not how you’d actually say “Yom Kippur” in Arabic. You might want to use عيد الغفران (ʿīd al-ghufrān), the “festival of forgiveness,” though calling it a “festival” when you’re supposed to be fasting strikes me as a little odd. يوم الغفران (yawm al-ghufrān) is also acceptable, and may actually be a little preferable, though I honestly am not sure on this one.