(ن) نَقَبَ يَنْقُبُ نَقْبًاnaqaba yanqubu naqban: to make a hole in leather or a wall, to breach. (This verb is not used in the Quran.)
نَقْبٌnaqb (verbal noun, maṣdar, also a noun, ism dhāt): a hole, a breach. Only once in the Quran, in the account of سدِّsddi Dhū l-Qarnayn: ﴿فَمَا اسْطَاعُوْٓا اَنْ يَّظْهَرُوْهُ وَمَا اسْتَطَاعُوْا لَهُۥ نَقْبًا﴾ (Al-Kahf 18:97)
(ک) نَقُبَ يَنْقُبُ نَقَابَةًnaquba yanqubu naqābatan: (1) to peer through a hole, i.e. to keep watch from a place where the watcher sees others but is not himself seen (2) (by extension) to be a chief, because the chief gathers information and watches over his people. (This verb is not used in the Quran.)
نَقِيْبٌnaqīb pl. نُقَبَآءُnuqabāʾu (adjective on the pattern of فَعِيْلٌfaʿīl): an overseer, a chief. Only once in the Quran: ﴿وَبَعَثْنَا مِنْهُمُ اثْنَيْ عَشَرَ نَقِيْبًا﴾ (Al-Māʾidah 5:12)
Form II (tafʿīl) نَقَّبَ يُنَقِّبُ تَنْقِيْبًاnaqqaba yunaqqibu tanqīban: to go to and fro (through the lands) a great deal, to roam about, to search through. Only once in the Quran: ﴿فَنَقَّبُوْا فِي الْبِلَادِ هَلْ مِنْ مَّحِيْصٍ﴾ (Qāf 50:36)