The affix śnam comes after the roots of the rudhādigaṇaḥ (7th Conjugation), in denoting an agent when a sārvadhātuka affix follows.,
This debars शप् The indicatory म् of the affix श्नम् shows that the affix न is to be placed after the last vowel of the root; see sutra 1.1.47. As रुध् + श्नम् + ति = रुध् + न + ति = रु + न + ध् + ति = रुणद्धि 'he obstructs'. So also भिनत्ति 'he splits'. The indicatory श is for the sake of sutra 6.4.23.,