(س) رَهِبَ يَرْهَبُ رَهْبَةً وَرَهَبًاrahiba yarhabu rahbatan wa-rahaban: to tremble and quake at heart at the thought of someone's greatness and majesty, to fear. ﴿وَاِيَّايَ فَارْهَبُوْنِ﴾ (Al-Baqarah 2:40)
رَهَبٌrahab / رَهْبَةٌrahbah (noun, ism dhāt): awe, dread, fear. ﴿وَيَدْعُوْنَنَا رَغَبًا وَّرَهَبًا﴾ (Al-Anbiyāʾ 21:90)
رُهْبَانٌruhbān (on the pattern of فُعْلَانٌfuʿlān; according to most, the plural of رَاهِبٌrāhib): those who fear God greatly, those who withdraw entirely from the world, monks. ﴿ذٰلِكَ بِاَنَّ مِنْهُمْ قِسِّيْسِيْنَ وَرُهْبَانًا﴾ (Al-Māʾidah 5:82)
رَهْبَانِيَّةٌrahbāniyyah: renouncing the world out of fear of God, monasticism. ﴿وَرَهْبَانِيَّةَۨ ابْتَدَعُوْهَا﴾ (Al-Ḥadīd 57:27)
Form IV (ifʿāl) اَرْهَبَ يُرْهِبُ اِرْهَابًاarhaba yurhibu irhāban: to frighten, to terrify. ﴿تُرْهِبُوْنَ بِهِۦ عَدُوَّ اللّٰهِ وَعَدُوَّكُمْ﴾ (Al-Anfāl 8:60)
Form X (istifʿāl) اِسْتَرْهَبَ يَسْتَرْهِبُ اِسْتِرْهَابًاistarhaba yastarhibu istirhāban: to terrify, to strike with dread. ﴿وَاسْتَرْهَبُوْهُمْ وَجَآءُوْ بِسِحْرٍ عَظِيْمٍ﴾ (Al-Aʿrāf 7:116)