ईषदसमाप्तौ कल्पब्देश्यदेशीयरः

Operational rule vidhi

The affixes कल्पप् (कल्प), देश्य and देशीयर् (देशीय) come after a nominal or verbal stem which connotes a slight incompleteness.

Word by word (padaccheda)

Right context ईषद्- असमाप्तौ saptamī · ekavacanaSubstitute / term कल्प - देश्य- देशीय अः prathamā · bahuvacana

Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.

Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.

Pink letters are it-markers (anubandhas), tags dropped by 1.3.9. Hover or tap one for the rule that marks it, or try the it-letter finder.

Full reading

ईषद्-असमाप्तौ कल्पप्-देश्य-देशीयरः

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

Commentary

The affixes कल्पप् (कल्प), देश्य and देशीयर् (देशीय) come after a nominal or verbal stem which connotes a slight incompleteness.
The word समाप्ति means 'fullness of objects'. A little non-fullness is called ईषदसमाप्ति ॥ Thus पटुकल्पः, पटुदेश्यः or पटुदेशीयः 'clever but slightly incomplete' i. e. 'tolerably clever'. मृदुकल्पः, मृदुदेश्यः, मृदुदेशीयः ॥ So also after verbs, as पचतिकल्पम्, जल्पतिकल्पम् ॥ &c.

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