غ م مgh-m-m
(ن) غَمَّ يَغُمُّ غَمًّاghamma yaghummu ghamman (original form: غَمَمَ يَغْمُمُghamama yaghmumu): to cover something. The lexicographers say that grief is called غَمّghamm because it covers over joy, and a cloud is called غَمَامghamām because it covers over the light. (This verb is not used in the Quran.)
غَمٌّghamm (also a noun (ism dhāt)): grief, sorrow. ﴿فَاَثَابَكُمْ غَمًّۢا بِغَمٍّ﴾ (Āl ʿImrān 3:153)
غَمَامٌghamām (generic noun (ism jins)): cloud. ﴿وَظَلَّلْنَا عَلَيْكُمُ الْغَمَامَ﴾ (Al-Baqarah 2:57)
غُمَّةٌghummah: an obscure, ambiguous and confused matter. ﴿ثُمَّ لَا يَكُنْ اَمْرُكُمْ عَلَيْكُمْ غُمَّةً﴾ (Yūnus 10:71)