The affix ghañ comes after a root when the sense is that of an appellative, the word being related to the verb from which its name is deduced, but not as agent.,
Thus प्रासः (i.e. प्रास्यन्ति तम्) 'a dart, lit. that which men throw'; प्रसेवः (i.e. प्रसीव्यन्ति तम्) 'a sack, lit. that which men stitch together'; आहारः (i.e. आहरन्ति अस्माद्रसम्) 'food, lit. that from which men take out the juice to nourish themselves'. As मधुराहारः, तक्षशिलाहारः ।
Why do we say 'not related as an agent'? Observe मेषः 'a sheep, lit. that which looks helplessly'. Here the word मेष is related to the verb मिषति as agent, and the affix is consequently not घञ्.
Why do we say 'when denoting an appellative'? Observe कर्तव्यः कटः 'the mat must be made'.
The force of च in the sutra is to indicate that घञ् may be applied irregularly in cases where appellative is not meant: as को भवता दायो दत्तः 'what gift was given by you'; को भवता लाभो लब्धः 'what gain was gained by you'.
The word कारक is used in the sutra for this purpose. The word अकर्तरि is a compound word formed by the negative नञ्. The word means a non-agent. Now the word 'non-agent' has two-fold significance; either it means any other karaka which is not an agent-karaka; or it may mean any thing in general which is not an agent. That is to say, the former negative, called पर्युदास, points out, by implication, the objects which are different from the thing prohibited; and in fact, makes the rule applicable to those objects, while the second sort of negative called प्रसज्य प्रतिषेध is a simple prohibition of the particular matter specified, without mentioning what is different from it. Giving the former interpretation to the word अकर्तरि, the word कारक becomes redundant, because 'non-agent' would mean any karaka other than an agent. But the very fact, that कारक is used, indicates the existence of the following rule which is nowhere expressly taught by Panini :-That नञ् is compounded even with the force of प्रसज्य प्रतिषेध. (VI. I. 45). अशित्, non-'sit'.
Both the phrases, 'when denoting mere condition (भाव)' and 'a karaka' 'which is not an agent' are understood in the succeeding aphorisms. See (II 2. 6) about नञ् Compound.,