अपे क्लेशतमसोः

Operational rule vidhi

The affix ड comes after the verb हन् 'to kill' when it is compounded with the preposition अप् and when the object in composition with it, is the word क्लेश 'pain' or तमस् 'darkness'.

Word by word (padaccheda)

Right context अपे saptamī · ekavacanaRight context क्लेश- तमसोः saptamī · dvivacana

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").

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

Full reading

अपे क्लेश-तमसोः

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

Commentary

The affix ड comes after the verb हन् 'to kill' when it is compounded with the preposition अप् and when the object in composition with it, is the word क्लेश 'pain' or तमस् 'darkness'.
As, क्लेशापहः पुत्रः 'the pain-allayer i. e. the son'; तमोपहः सूर्यः 'the darkness-destroyer i. e. the sun'.

This aphorism has its scope when the sense is not that of benediction.

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