6.2.174
ह्रस्वान्तेऽन्त्यात् पूर्वम्
Operational rule vidhi
When the compound ends in a light vowel the acute accent (उदात्त) falls on the syllable before such last, in a बहुव्रीहि समास preceded by नञ् and सु to which the affix कप् -- नद्यृतश्च (5.4.153), is added.
Word by word (padaccheda)
Right context ह्रस्वान्ते saptamī · ekavacanaLeft context अन्त्यात् pañcamī · ekavacanaSubstitute / term पूर्वम् prathamā · ekavacana
- 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").
- Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
Full reading
ह्रस्वान्ते अन्त्यात् पूर्वम्
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
When the compound ends in a light vowel the acute accent (उदात्त) falls on the syllable before such last, in a बहुव्रीहि समास preceded by नञ् and सु to which the affix कप् -- नद्यृतश्च 5.4.153, is added.
Thus अय꣡वकोदेशः, अव्री꣡हिकः, अमा꣡षकः, सुय꣡वकः, सुव्री꣡हिकः, सुमा꣡꣡षकः ॥ The repetition of पूर्व in this sutra, though its anuvritti was present from the last shows, that in the last aphorism, the syllable preceding कप् takes the acute, while here the syllable preceding the short-vowel-ending final syllable has the acute and not the syllable preceding कप् ॥ This is possible with a word which is, at least, of two syllables (not counting, of course, सु and क or कप्). Therefore, in अज्ञ꣡कः and सुज्ञ꣡कः, the acute is on the syllable preceding कप् by 6.2.173, because it has here no antyat-purvam.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.