Surah An-Naba 78:14

وَأَنزَلْنَا مِنَ ٱلْمُعْصِرَٰتِ مَآءً ثَجَّاجًا

And sent down, from the rain clouds, pouring water.

Translation: Saheeh International

Tafsir

and sent down from the rain-clouds mu‘sirāt the clouds due to give rain similar to the term mu‘sir which denotes a girl nearing menstruation cascading water? pouring forth

Excerpt from Tafsir al-Jalalayn, commentary on 78:14, via Quran.com. The reader has the full commentary and 9 more tafsirs.