نَفْسٍ

A word in the Arabic language will either be 1) a verb or 2) a noun or 3) a particle – نَفْسٍ is a noun

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

نَفْسٌ is the natural state of this indefinite noun and it becomes نَفْسٍ due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

Soul, Person, Self, Spirit, Mind, Inner desire or feeling, Willingly (when used as adverb)

To be precious, in request, console, cheer

Surah/Below are the 35 verses in the holy Quran, containing the indefinite, genitive nounنَفْسٍ
Verse 
And fear a day when a person shall not avail anotherوَاتَّقُوْا يَوْمًا لَّا تَجْزِي نَفْسٌ عَنْ نَفْسٍ شَيْئًا
nor will intercession be accepted from himوَلَا يُقْبَلُ مِنْهَا شَفَاعَةٌ
2-48nor will compensation be taken from him, nor will they be helpedوَلَا يُؤْخَذُ مِنْهَا عَدْلٌ وَلَا هُمْ يُنْصَرُوْنَ
2-123
2-281
3-25
3-30
3-145
3-161
3-185
4-1
5-32
6-98
6-164
7-189
10-30
10-54
10-100
13-33
13-42
14-51
16-111
18-74
20-15
21-35
29-57
31-28
32-13
39-6
39-70
40-17
45-22
50-21
74-38
82-19
86-4
91-7and a soul and Who proportioned itوَنَفْسٍ وَمَا سَوَّاهَا