The affix ṅīṣ is optionally used in the feminine after a bahuvrīhi samāsa ending with the word in kta having acute accent on the final, the antecedent word not being a word denoting a part of the body.,
The words अन्तोदात्तात् and क्तान्तात् govern this sutra. This aphorism lays down an option, where by the last aphorism, it would have been compulsory. Thus शार्ङ्गजग्ध, is a word having acute accent on the final 6.2.170, but as the first portion of this Bahuvrihi is not a Svanga word, but a jati word, its feminine will be शार्ङ्गजग्धी or शार्ङ्गजग्धा ॥ So also पलाण्डुभक्षिती or पलाण्डुभक्षिता and सुरापीती or सुरापीता.
Why do we say 'when the first member of the compound is not a svanga word'? Observe शंखभिन्नी, ऊरुभिन्नी which admit of only one form.
If the final is not acutely accented, the rule will not apply. As वस्त्रछन्ना and वसनछन्ना which are not acutely accented on the final (See VI. 2. 170), because the first member is a word denoting dress or आच्छादन, which is especially excepted from the scope of rule 6.2.170.
Vart:- Diversely in the Chhandas and in Names. As प्रवृद्धविलूनी or प्रवृद्धविलूना ॥,