ھ د دh-d-d
(ن، ض) هَدَّ يَهُدُّ وَيَهِدُّ هَدًّاhadda yahuddu wa-yahiddu haddan (original form: هَدَدَhadada): to bring something down with a loud crash, to demolish; (intransitive) to fall with a crash. (This verb is not used in the Quran.)
هَدٌّhadd (verbal noun, maṣdar): falling with a crash, crumbling to pieces. Only once in the Quran: ﴿تَكَادُ السَّمٰوٰتُ يَتَفَطَّرْنَ مِنْهُ وَتَنْشَقُّ الْاَرْضُ وَتَخِرُّ الْجِبَالُ هَدًّا﴾ (Maryam 19:90)