Pāṇini sūtras

A Tat-purusha compound, with the exception of that which is formed by the particle nañ, and of the Karmadhâraya compound, becomes neuter gender, in the cases explained in the following sûtras.

1. tatpuruṣaḥतत्पुरुषः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   tत्	tatpuruṣaतत्पुरुष	tatpuruṣaḥतत्पुरुषः	tatpuruṣaतत्पुरुष	tatpuruṣतत्पुरुष् + plus aḥअः

2. a+nañ+karmadhārayaḥअ+नञ्+कर्मधारयः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	aअ	aअ	not	aअ
   nन्	nañनञ्	nañनञ्	nañनञ्	nañनञ्
   kक्	karmadhārayaकर्मधारय	karmadhārayaḥकर्मधारयः	karmadhārayaकर्मधारय	karmadhārayकर्मधारय् + plus aḥअः

Anuvṛtti

1. napuṃsakamनपुंसकम् 2·4·17

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   nन्	napuṃsakaनपुंसक	napuṃsakamनपुंसकम्	neuter	napuṃsakनपुंसक् + plus amअम्