The affix ṇamul comes after a root when an object or an agent denoting similitude is in composition with it.,
The word 'agent' is read into the sutra, by virtue of the word च 'also'. That with which any thing is compared is called उपमान or 'object of comparison or similitude'. As घृतनिधायम् निहितम् जलम् 'water was kept as ghee would be kept'. सुवर्णनिधायम् निहितः 'was kept as gold'. The force is that of इव; thus घृतनिधायम् निहितः = घृतमिव निहितः । So also when the object of comparison is as agent: thus, अजनाशे नष्टः 'he perished like a goat'. So also चूडकनाशम् दन्तनाशम्, &c.,