The affix khyun , when in the sense of the word to be formed is that of an instrumental agent, comes after the verb kṛ 'to make', when the following words are in composition with it - 1. āḍhya 'rich' 2. subhaga 'fortunate' 3. sthūla 'big' 4. palita 'grey' 5. nagna 'naked' 6. andha 'blind' 7. priya 'pleasant', provided these words formed by the affix cvi though not actually ending in the affix cvi,
The affix च्वि (V. 4. 50.) is added to a noun when it is in composition with the verbs भू 'to become', कृ 'to make' and अस् 'to be'; its force being that a thing attains to a condition in which it previously was not. The च्वि being an optional affix, its sense is two-fold; namely, words ending in च्वि and words not ending in च्वि. Both may have the force of च्वि. In the present sutra, however, the words that actually end in च्वि have been excluded, while words which do not take the affix च्वि, but have the force of च्वि are included in the present sutra.
Thus आढ्य + कृ + ख्युन् = आढ्य + कर् + अन् = आढ्यं करणं 'that by the instrumentality of which the poor becomes rich, viz., wealth, prosperity, means of enriching'; सुभगङ्करणम् 'making happy'; स्थूलङ्करणम् 'by which one becomes big'; पलितङ्करणम् 'rendering grey'; नग्नङ्करणम् 'making naked'; अन्धङ्करणम् 'making blind'; प्रियङ्करणम् 'showing kindness'.
Why do we say 'when the force is that of the affix च्वि'? Otherwise आढ्यं तैलेन कुर्वन्ति i.e अभ्यजयन्ति 'they anoint with oil'. Here though something is joined with what it previously was not joined, namely with oil, yet as the radical word is not prominent here, the sense is not that of च्वि and hence this counter-example.
Why do we say 'when not ending in the affix च्वि'? Observe आढ्यी कुर्वन्ति अनेन 'they make rich by this'. Here the affix ख्युन् is not employed.
It might be objected : 'well if ख्युन् is not used, then the affix ल्युट् must be used 3.3.117 as there is no difference between ख्युन् and ल्युट्; both having the efficient portion यु; what is then the use of prohibiting च्वि? We reply, 'because there is this prohibition, when the affix ख्युन् is not employed the affix ल्युट् will also be not employed. Thus by implication the affix ल्युट् is also prohibited. The prohibition of च्वि in this sutra is for the sake of the aphorisms that follow'.
Patanjali observes this prohibition as superfluous, because there is no distinction between ल्युट् and ख्युन्. For the word formed by any one of these affixes have the same form and the same accent. Nor there is any distinction in the feminines of their derivatives. For the word formed by नञ्, स्नञ्, ईक्, अक् and ख्युन् take ई in the feminine as well as the words तरुन and तलन. Nor there is any distinction in their samasas. For in both the cases it will be nitya samasa. Nor is the prohibition made for the sake of the augment मुम्. For it being an indeclinable, मुम् cannot come after it. The prohibition therefore is of no use to this sutra but it is inserted here for the sake of the following sutras.,