• تَظْمَؤُا۟
• ظَمَأ
• ظَّمْـَٔان

Appears 3 times in the Quran.

1. 9:120 مَا كَانَ لِأَهْلِ ٱلْمَدِينَةِ وَمَنْ حَوْلَهُم مِّنَ ٱلْأَعْرَابِ أَن يَتَخَلَّفُوا۟ عَن رَّسُولِ ٱللَّهِ وَلَا يَرْغَبُوا۟ بِأَنفُسِهِمْ عَن نَّفْسِهِۦ ذَٰلِكَ بِأَنَّهُمْ لَا يُصِيبُهُمْ ظَمَأٌ وَلَا نَصَبٌ وَلَا مَخْمَصَةٌ فِى سَبِيلِ ٱللَّهِ وَلَا يَطَـُٔونَ مَوْطِئًا يَغِيظُ ٱلْكُفَّارَ وَلَا يَنَالُونَ مِنْ عَدُوٍّ نَّيْلًا إِلَّا كُتِبَ لَهُم بِهِۦ عَمَلٌ صَٰلِحٌ إِنَّ ٱللَّهَ لَا يُضِيعُ أَجْرَ ٱلْمُحْسِنِينَ

   It did not beseem the people of Medina and those round about them of the dwellers of the desert to remain behind the Messenger of Allah, nor should they desire (anything) for themselves in preference to him; this is because there afflicts them not thirst or fatigue or hunger in Allah's way, nor do they tread a path which enrages the unbelievers, nor do they attain from the enemy what they attain, but a good work is written down to them on account of it; surely Allah does not waste the reward of the doers of good;
   

2. 20:119 وَأَنَّكَ لَا تَظْمَؤُا۟ فِيهَا وَلَا تَضْحَىٰ

   And that you shall not be thirsty therein nor shall you feel the heat of the sun.
   

3. 24:39 وَٱلَّذِينَ كَفَرُوٓا۟ أَعْمَٰلُهُمْ كَسَرَابٍۭ بِقِيعَةٍ يَحْسَبُهُ ٱلظَّمْـَٔانُ مَآءً حَتَّىٰٓ إِذَا جَآءَهُۥ لَمْ يَجِدْهُ شَيْـًٔا وَوَجَدَ ٱللَّهَ عِندَهُۥ فَوَفَّىٰهُ حِسَابَهُۥ وَٱللَّهُ سَرِيعُ ٱلْحِسَابِ

   And (as for) those who disbelieve, their deeds are like the mirage in a desert, which the thirsty man deems to be water; until when he comes to it he finds it to be naught, and there he finds Allah, so He pays back to him his reckoning in full; and Allah is quick in reckoning;