• غَاسِق
• غَسَّاق
• غَسَق

Appears 4 times in the Quran.

1. 17:78 أَقِمِ ٱلصَّلَوٰةَ لِدُلُوكِ ٱلشَّمْسِ إِلَىٰ غَسَقِ ٱلَّيْلِ وَقُرْءَانَ ٱلْفَجْرِ إِنَّ قُرْءَانَ ٱلْفَجْرِ كَانَ مَشْهُودًا

   Keep up prayer from the declining of the sun till the darkness of the night and the morning recitation; surely the morning recitation is witnessed.
   

2. 38:57 هَٰذَا فَلْيَذُوقُوهُ حَمِيمٌ وَغَسَّاقٌ

   This (shall be so); so let them taste it, boiling and intensely cold (drink).
   

3. 78:25 إِلَّا حَمِيمًا وَغَسَّاقًا

   But boiling and intensely cold water,
   

4. 113:3 وَمِن شَرِّ غَاسِقٍ إِذَا وَقَبَ

   And from the evil of the utterly dark night when it comes,