According to the opinion of Northern Grammarians, the affix iñ comes in the sense of descendant after the words ending in senā , the word lakṣaṇa and words expressing artisans.,
Thus कारिषेणिः, हारिषेणिः, लाक्षणिः, तान्तुवायिः, कौम्भकारिः ॥ As to the word तक्ष्ण 'carpenter.' See 4.1.112. It will have ताक्ष्णः and ताक्ष्ण्यः, but will not take इञ् ॥ The word नापित being a Vriddha, non-gotra word, will take फिञ् under 4.1.157 according to the Northern Grammarians, as नापितायनिः ॥,