In this chapter, we will cover the declension of regular nouns ending with ṛ, o, ai and au. As always, we will show the tables of endings for each kind of vowel ending, and the rule is to drop the final vowel (ṛ, o, ai or au) of the noun that you wish to inflect, and add the appropriate ending.
There are two regular patterns of declension for nouns ending in ṛ1Müller, "A Sanskrit grammar for beginners", p. 113, §235: 1) The first pattern, that we are calling "Type 1" here, is generally followed by nouns that end with the suffix tṛ and denote the agent or the doer of an action. For example: kartṛ (that means "doer" or "one who does"), hotṛ (that means "sacrificer" or "one who sacrifices") and bhartṛ (that means "husband"). 2) The second pattern, that we are calling "Type 2" here, is followed by most terms of family relationship. For example, bhrātṛ ("brother"), mātṛ ("mother"), and pitṛ ("father"). The exceptions are
Below are the declension tables for Types 1 and 2. For the masculine and feminine genders, the ones for Type 1 are shown on the left and the corresponding ones for Type 2 are shown on the right. There is no neuter table of endings for Type 2. Notice that the only differences of Type 2 with respect to Type 1 are in the Accusative singular, Nominative/Accusative/Vocative dual and Nominative plural.
Endings: Type 1 masculine nouns in ṛ
| Endings: Type 2 masculine nouns in ṛ
|
Endings: Type 1 feminine nouns in ṛ
| Endings: Type 2 feminine nouns in ṛ
|
Endings: Type 1 neuter nouns in ṛ
| Singular | Dual | Plural | |
| Nominative | ऋ ṛ | ऋणी ṛṇī | ॠणि ṝṇi |
| Vocative | अः aḥ | आरौ ārau | आरः āraḥ |
| Accusative | आरम् āram | आरौ ārau | ॠन् ṝn |
| Instrumental | ऋणा ṛṇā (or) रा rā | ऋभ्याम् ṛbhyām | ऋभिः ṛbhiḥ |
| Dative | ऋणे ṛṇe (or) रे re | ऋभ्याम् ṛbhyām | ऋभ्यः ṛbhyaḥ |
| Ablative | ऋणः ṛṇaḥ (or) उः uḥ | ऋभ्याम् ṛbhyām | ऋभ्यः ṛbhyaḥ |
| Genitive | ऋणः ṛṇaḥ (or) उः uḥ | ऋणोः ṛṇoḥ (or) रोः roḥ | ॠणाम् ṝṇām |
| Locative | ऋणि ṛṇi (or) अरि ari | ऋणोः ṛṇoḥ (or) रोः roḥ | ऋषु ṛṣu |
As examples of Type 1 nouns, below are the declension tables of the masculine noun naptṛ ("grandson"), the feminine noun svasṛ ("sister") and the neuter form of kartṛ ("doer"):
Naptṛ (masculine)
| Singular | Dual | Plural | |
| Nominative | नप्ता naptā | नप्तारौ naptārau | नप्तारः naptāraḥ |
| Vocative | नप्तः naptaḥ | नप्तारौ naptārau | नप्तारः naptāraḥ |
| Accusative | नप्तारम् naptāram | नप्तारौ naptārau | नप्तॄन् naptṝn |
| Instrumental | नप्त्रा naptrā | नप्तृभ्याम् naptṛbhyām | नप्तृभिः naptṛbhiḥ |
| Dative | नप्त्रे naptre | नप्तृभ्याम् naptṛbhyām | नप्तृभ्यः naptṛbhyaḥ |
| Ablative | नप्तुः naptuḥ | नप्तृभ्याम् naptṛbhyām | नप्तृभ्यः naptṛbhyaḥ |
| Genitive | नप्तुः naptuḥ | नप्त्रोः naptroḥ | नप्तॄणाम् naptṝṇām |
| Locative | नप्तरि naptari | नप्त्रोः naptroḥ | नप्तृषु naptṛṣu |
Svasṛ (feminine)
| Singular | Dual | Plural | |
| Nominative | स्वसा svasā | स्वसारौ svasārau | स्वसारः svasāraḥ |
| Vocative | स्वसः svasaḥ | स्वसारौ svasārau | स्वसारः svasāraḥ |
| Accusative | स्वसारम् svasāram | स्वसारौ svasārau | स्वसॄः svasṝḥ |
| Instrumental | स्वस्रा svasrā | स्वसृभ्याम् svasṛbhyām | स्वसृभिः svasṛbhiḥ |
| Dative | स्वस्रे svasre | स्वसृभ्याम् svasṛbhyām | स्वसृभ्यः svasṛbhyaḥ |
| Ablative | स्वसुः svasuḥ | स्वसृभ्याम् svasṛbhyām | स्वसृभ्यः svasṛbhyaḥ |
| Genitive | स्वसुः svasuḥ | स्वस्रोः svasroḥ | स्वसॄणाम् svasṝṇām |
| Locative | स्वसरि svasari | स्वस्रोः svasroḥ | स्वसृषु svasṛṣu |
Kartṛ (neuter)
| Singular | Dual | Plural | |
| Nominative | कर्तृ kartṛ | कर्तृणी kartṛṇī | कर्तॄणि kartṝṇi |
| Vocative | कर्तः kartaḥ | कर्तारौ kartārau | कर्तारः kartāraḥ |
| Accusative | कर्तारम् kartāram | कर्तारौ kartārau | कर्तॄन् kartṝn |
| Instrumental | कर्तृणा kartṛṇā (or) कर्त्रा kartrā | कर्तृभ्याम् kartṛbhyām | कर्तृभिः kartṛbhiḥ |
| Dative | कर्तृणे kartṛṇe (or) कर्त्रे kartre | कर्तृभ्याम् kartṛbhyām | कर्तृभ्यः kartṛbhyaḥ |
| Ablative | कर्तृणः kartṛṇaḥ (or) कर्तुः kartuḥ | कर्तृभ्याम् kartṛbhyām | कर्तृभ्यः kartṛbhyaḥ |
| Genitive | कर्तृणः kartṛṇaḥ (or) कर्तुः kartuḥ | कर्तृणोः kartṛṇoḥ (or) कर्त्रोः kartroḥ | कर्तॄणाम् kartṝṇām |
| Locative | कर्तृणि kartṛṇi (or) कर्तरि kartari | कर्तृणोः kartṛṇoḥ (or) कर्त्रोः kartroḥ | कर्तृषु kartṛṣu |
As examples of Type 2 nouns, below are the declension tables of pitṛ ("father") and mātṛ ("mother"):
Pitṛ (masculine)
| Singular | Dual | Plural | |
| Nominative | पिता pitā | पितरौ pitarau | पितरः pitaraḥ |
| Vocative | पितः pitaḥ | पितरौ pitarau | पितरः pitaraḥ |
| Accusative | पितरम् pitaram | पितरौ pitarau | पितॄन् pitṝn |
| Instrumental | पित्रा pitrā | पितृभ्याम् pitṛbhyām | पितृभिः pitṛbhiḥ |
| Dative | पित्रे pitre | पितृभ्याम् pitṛbhyām | पितृभ्यः pitṛbhyaḥ |
| Ablative | पितुः pituḥ | पितृभ्याम् pitṛbhyām | पितृभ्यः pitṛbhyaḥ |
| Genitive | पितुः pituḥ | पित्रोः pitroḥ | पितॄणाम् pitṝṇām |
| Locative | पितरि pitari | पित्रोः pitroḥ | पितृषु pitṛṣu |
Mātṛ (feminine)
| Singular | Dual | Plural | |
| Nominative | माता mātā | मातरौ mātarau | मातरः mātaraḥ |
| Vocative | मातः mātaḥ | मातरौ mātarau | मातरः mātaraḥ |
| Accusative | मातरम् mātaram | मातरौ mātarau | मातॄः mātṝḥ |
| Instrumental | मात्रा mātrā | मातृभ्याम् mātṛbhyām | मातृभिः mātṛbhiḥ |
| Dative | मात्रे mātre | मातृभ्याम् mātṛbhyām | मातृभ्यः mātṛbhyaḥ |
| Ablative | मातुः mātuḥ | मातृभ्याम् mātṛbhyām | मातृभ्यः mātṛbhyaḥ |
| Genitive | मातुः mātuḥ | मात्रोः mātroḥ | मातॄणाम् mātṝṇām |
| Locative | मातरि mātari | मात्रोः mātroḥ | मातृषु mātṛṣu |
The only noun ending with o that is worth mentioning here is go, which can mean "cow" if it is feminine, or "ox" if it is masculine2Müller, "A Sanskrit grammar for beginners", p. 97, §218. In both genders, it is declined the same way. Below is the declension table of go:
Go (feminine)
| Singular | Dual | Plural | |
| Nominative | गौः gauḥ | गावौ gāvau | गावः gāvaḥ |
| Vocative | गौः gauḥ | गावौ gāvau | गावः gāvaḥ |
| Accusative | गाम् gām | गावौ gāvau | गाः gāḥ |
| Instrumental | गवा gavā | गोभ्याम् gobhyām | गोभिः gobhiḥ |
| Dative | गवे gave | गोभ्याम् gobhyām | गोभ्यः gobhyaḥ |
| Ablative | गोः goḥ | गोभ्याम् gobhyām | गोभ्यः gobhyaḥ |
| Genitive | गोः goḥ | गवोः gavoḥ | गवाम् gavām |
| Locative | गवि gavi | गवोः gavoḥ | गोषु goṣu |
Nouns in ai and au are also very rare. They are declined using the following tables of endings3Müller, "A Sanskrit grammar for beginners", p. 97, §217:
Endings for nouns in ai
| Endings for nouns in au
|
Below are the declension tables of rai (a masculine noun meaning "wealth") and nau (a feminine noun meaning "ship"):
Rai (masculine)
| Nau (feminine)
|