अपथं नपुंसकम्

Operational rule vidhi

The तत्-पुरुष word अपथम् 'a bad road', is neuter.

Word by word (padaccheda)

Substitute / term अपथम् prathamā · ekavacanaSubstitute / term नपुंसकम् prathamā · ekavacana

Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.

Full reading

अपथम् नपुंसकम्

Commentary

The तत्-पुरुष word अपथम् 'a bad road', is neuter.
अपथमिदम् 'this (neuter) is a bad road' अपथानि गाहते मूढः 'the fool roams on wrong roads.' But अपथोदेशः a (masc.) 'a roadless country.' Here the compound being Bahuvrihi the word is masculine so; also अपथा नगरी ॥

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.