(ض) فَقَرَ يَفْقِرُ فَقْرًاfaqara yafqiru faqran: the original meaning is to break a vertebra (فَقَارfaqār) of the spine; hence فَقِيْرfaqīr, as it were one whose back has been broken. In the sense of being needy, (ک) فَقُرَ يَفْقُرُ فَقَارَةًfaqura yafquru faqāratan is also reported. (This verb is not used in the Quran.)
فَقْرٌfaqr (noun, ism dhāt): need, poverty. ﴿اَلشَّيْطٰنُ يَعِدُكُمُ الْفَقْرَ﴾ (Al-Baqarah 2:268)
فَقِيْرٌfaqīr pl. فُقَرَآءُfuqarāʾu (فَعِيْلٌfaʿīl in the sense of a passive participle): needy, poor. ﴿يٰٓاَيُّهَا النَّاسُ اَنْتُمُ الْفُقَرَآءُ اِلَي اللّٰهِ﴾ (Fāṭir 35:15); ﴿اِنْ يَّكُوْنُوْا فُقَرَآءَ يُغْنِهِمُ اللّٰهُ مِنْ فَضْلِهِۦ﴾ (An-Nūr 24:32)
فَاقِرَةٌfāqirah (active participle, ism fāʿil): a back-breaking, grievous calamity. ﴿تَظُنُّ اَنْ يُّفْعَلَ بِهَا فَاقِرَةٌ﴾ (Al-Qiyāmah 75:25)