Sanskrit i-stems · agni, gati, vāri

	agni Masculine · “fire”
Nom.	agniḥ	agnī	agnayaḥ
Acc.	agnim	agnī	agnīn
Ins.	agninā	agnibhyām	agnibhiḥ
Dat.	agnaye	agnibhyām	agnibhyaḥ
Abl.	agneḥ	agnibhyām	agnibhyaḥ
Gen.	agneḥ	agnyoḥ	agnīnām
Loc.	agnau	agnyoḥ	agniṣu
Voc.	agne	agnī	agnayaḥ

Coral marks the masculine-only singular endings: -inā (ins.), -aye (dat.), -eḥ (abl./gen.), -au (loc.), plus the masculine acc. pl. -īn. Every other cell is shared with the feminine below.

	gati Feminine · “going, path”
Nom.	gatiḥ	gatī	gatayaḥ
Acc.	gatim	gatī	gatīḥ
Ins.	gatyā	gatibhyām	gatibhiḥ
Dat.	gatyai	gatibhyām	gatibhyaḥ
Abl.	gatyāḥ	gatibhyām	gatibhyaḥ
Gen.	gatyāḥ	gatyoḥ	gatīnām
Loc.	gatyām	gatyoḥ	gatiṣu
Voc.	gate	gatī	gatayaḥ

Coral marks the feminine -y- glide in the singular obliques: gatyā, gatyai, gatyāḥ, gatyām, plus the dual gatyoḥ and the feminine acc. pl. -īḥ (with visarga, not -īn). The same six slots that were masculine-marked in agni now carry the feminine signature.

	vāri Neuter · “water”
Nom.	vāri	vāriṇī	vārīṇi
Acc.	vāri	vāriṇī	vārīṇi
Ins.	vāriṇā	vāribhyām	vāribhiḥ
Dat.	vāriṇe	vāribhyām	vāribhyaḥ
Abl.	vāriṇaḥ	vāribhyām	vāribhyaḥ
Gen.	vāriṇaḥ	vāriṇoḥ	vārīṇām
Loc.	vāriṇi	vāriṇoḥ	vāriṣu
Voc.	vāre	vāriṇī	vārīṇi

Coral marks the neuter -ṇ- infix. The -n- (retroflexed to -ṇ- after i) is inserted before every vowel ending in the oblique cases — ins., dat., abl., gen., loc. singular and the gen./loc. dual — and appears again in the nom./acc./voc. dual and plural.

1. The rule

Short i-stems (Whitney §336–342; MacDonell §85) are a three-gender paradigm. Masculine and feminine stems share the same baseline but split in six singular cells — the feminine adopting the -y- glide pattern familiar from nadī. Neuters take their own path entirely: an -n- infix (retroflexed to -ṇ- after i) fills every oblique cell in the singular and dual.

2. How to remember

i Masc vs. fem diverge in six singular cells. From the instrumental onward, masculines use -inā, -aye, -eḥ, -au and feminines use -yā, -yai, -yāḥ, -yām. Acc. pl. also differs: agnīn (m., with -n) vs. gatīḥ (f., with visarga). That's the sharpest gender signal.
ii The neuter inserts -ṇ-. Every oblique cell in the singular and dual (and the nom/acc/voc du, nom/acc/voc pl) gets an -n- between stem and ending, retroflexed to -ṇ- because the preceding vowel is -i- (the ruki rule): vār-iṇ-ā, vār-iṇ-e, vār-iṇ-aḥ, vār-iṇ-i, vār-iṇ-ī, vār-iṇ-oḥ. Before consonant endings the -n- drops: vāri-bhyām, vāri-bhiḥ, vāri-ṣu.
iii Nom/acc pl neuter lengthens the stem vowel and keeps the retroflex -ṇ-: vārīṇi. The long ī is the plural marker of neuter vowel stems in general — you'll see the same pattern in u-stem neuters (madhūni “honeys”) and -as neuters (tapāṃsi “austerities”).
iv The dual is always just three forms. For all three genders: -ī or -iṇī (nom/acc/voc), -ibhyām (ins/dat/abl), -yoḥ or -iṇoḥ (gen/loc).

3. Exercise — all three genders

Three paradigms, 72 forms. Pay attention to the gender splits in singular oblique cases and to the neuter -ṇ- infix.

	agni Masculine · “fire”
	Singular	Dual	Plural
Nom.
Acc.
Ins.
Dat.
Abl.
Gen.
Loc.
Voc.

	gati Feminine · “going, path”
	Singular	Dual	Plural
Nom.
Acc.
Ins.
Dat.
Abl.
Gen.
Loc.
Voc.

	vāri Neuter · “water”
	Singular	Dual	Plural
Nom.
Acc.
Ins.
Dat.
Abl.
Gen.
Loc.
Voc.

0 / 72 correct