A neuter s-stem absorbed into a possessive compound becomes masculine. The paradigm below shows what actually changes — and, perhaps more usefully, how little.
| tapas Neuter · “austerity” | kṛtsna-tapāḥ Masculine · Bahuvrīhi | |||||
|---|---|---|---|---|---|---|
| Singular | Dual | Plural | Singular | Dual | Plural | |
| Nom. | tapaḥ |
tapasī |
tapāṃsi |
°tapāḥ |
°tapasau |
°tapasaḥ |
| Acc. | tapaḥ |
tapasī |
tapāṃsi |
°tapasam |
°tapasau |
°tapasaḥ |
| Ins. | tapasā |
tapobhyām |
tapobhiḥ |
°tapasā |
°tapobhyām |
°tapobhiḥ |
| Dat. | tapase |
tapobhyām |
tapobhyaḥ |
°tapase |
°tapobhyām |
°tapobhyaḥ |
| Abl. | tapasaḥ |
tapobhyām |
tapobhyaḥ |
°tapasaḥ |
°tapobhyām |
°tapobhyaḥ |
| Gen. | tapasaḥ |
tapasoḥ |
tapasām |
°tapasaḥ |
°tapasoḥ |
°tapasām |
| Loc. | tapasi |
tapasoḥ |
tapaḥsu |
°tapasi |
°tapasoḥ |
°tapaḥsu |
Cells marked in peach are where the masculine bahuvrīhi diverges from the neuter paradigm. The long ā is the single place in the whole table where the stem vowel lengthens.
A neuter -as stem used as the head of a bahuvrīhi is re-gendered to match its referent. Only the nominative and accusative forms — in singular, dual and plural — diverge from the neuter paradigm. Everything else (instrumental, dative, ablative, genitive, locative, across all three numbers) is identical in the two paradigms. The vowel lengthening a → ā appears in exactly one cell, the nominative singular: the familiar compensatory lengthening of masculine -as stems (Whitney §418; Pāṇini 6.4.14 atvasantasya ca).
Four rows diverge. Memorise them, and the rest is free:
Fill in both paradigms. The neuter manas (“mind”) is the textbook -as-stem; the bahuvrīhi sumanas is its masculine derivative. Each cell validates as you type — use macrons and dot-unders (ā, ī, ū, ḥ, ṃ, ṇ).
| manas Neuter · “mind” | |||
|---|---|---|---|
| Singular | Dual | Plural | |
| Nom. | |||
| Acc. | |||
| Ins. | |||
| Dat. | |||
| Abl. | |||
| Gen. | |||
| Loc. | |||
| sumanas Masculine · Bahuvrīhi adj. well-minded, benevolent, cheerful · m. n. flower | |||
|---|---|---|---|
| Singular | Dual | Plural | |
| Nom. | |||
| Acc. | |||
| Ins. | |||
| Dat. | |||
| Abl. | |||
| Gen. | |||
| Loc. | |||