• دَاحِضَة
• مُدْحَضِين
• يُدْحِضُوا۟

Appears 4 times in the Quran.

1. 18:56 وَمَا نُرْسِلُ ٱلْمُرْسَلِينَ إِلَّا مُبَشِّرِينَ وَمُنذِرِينَ وَيُجَٰدِلُ ٱلَّذِينَ كَفَرُوا۟ بِٱلْبَٰطِلِ لِيُدْحِضُوا۟ بِهِ ٱلْحَقَّ وَٱتَّخَذُوٓا۟ ءَايَٰتِى وَمَآ أُنذِرُوا۟ هُزُوًا

   And We do not send messengers but as givers of good news and warning, and those who disbelieve make a false contention that they may render null thereby the truth, and they take My communications and that with which they are warned for a mockery.
   

2. 37:141 فَسَاهَمَ فَكَانَ مِنَ ٱلْمُدْحَضِينَ

   So he shared (with them), but was of those who are cast off.
   

3. 40:5 كَذَّبَتْ قَبْلَهُمْ قَوْمُ نُوحٍ وَٱلْأَحْزَابُ مِنۢ بَعْدِهِمْ وَهَمَّتْ كُلُّ أُمَّةٍۭ بِرَسُولِهِمْ لِيَأْخُذُوهُ وَجَٰدَلُوا۟ بِٱلْبَٰطِلِ لِيُدْحِضُوا۟ بِهِ ٱلْحَقَّ فَأَخَذْتُهُمْ فَكَيْفَ كَانَ عِقَابِ

   The people of Nuh and the parties after them rejected (prophets) before them, and every nation purposed against their messenger to destroy him, and they disputed by means of the falsehood that they might thereby render null the truth, therefore I destroyed them; how was then My retribution!
   

4. 42:16 وَٱلَّذِينَ يُحَآجُّونَ فِى ٱللَّهِ مِنۢ بَعْدِ مَا ٱسْتُجِيبَ لَهُۥ حُجَّتُهُمْ دَاحِضَةٌ عِندَ رَبِّهِمْ وَعَلَيْهِمْ غَضَبٌ وَلَهُمْ عَذَابٌ شَدِيدٌ

   And (as for) those who dispute about Allah after that obedience has been rendered to Him, their plea is null with their Lord, and upon them is wrath, and for them is severe punishment.