प्रसितोत्सुकाभ्यां तृतीया च

Operational rule vidhi

In conjunction with the words प्रसिक्त and उत्सुक 'greatly desirous of', the 3rd case-affix is used after the word, as well as the 7th.

Word by word (padaccheda)

With / by प्रसित- उत्सुकाभ्याम् tṛtīyā · dvivacanaSubstitute / term तृतीया prathamā · ekavacanaIndeclinable च avyaya

With / by Tṛtīyā (3rd case): accompaniment or means.
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
Indeclinable An avyaya such as च "and", वा "optionally", न "not".

Full reading

प्रसित-उत्सुकाभ्याम् तृतीया च

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

In conjunction with the words प्रसिक्त and उत्सुक 'greatly desirous of', the 3rd case-affix is used after the word, as well as the 7th.
Ex. निद्रायां निद्रया वा उत्सुकः 'longing for sleep,' केशैः or केशेषु प्रसितः

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