ر ج جr-j-j
(ن) رَجَجَ يَرْجُجُrajaja yarjuju (original) ⟵ رَجَّ يَرُجُّ رَجًّاrajja yarujju rajjan: to shake violently, to convulse.
رَجّrajj (verbal noun, maṣdar): a violent quaking. Twice in the Quran, both in the same place: ﴿اِذَا رُجَّتِ الْاَرْضُ رَجًّا﴾ (Al-Wāqiʿah 56:4) — a passive verb with its verbal noun (maṣdar) as a cognate accusative (mafʿūl muṭlaq) for emphasis.