-ई

• (Delhi Hindi) IPA^(key): /iː/

All forms are ultimately from Sanskrit -इक (-ika):

• Direct singular inherited from Sauraseni Apabhramsa -इउ (-iu), from Sauraseni Prakrit -𑀇𑀕𑁄 (-igo), from Sanskrit -इकः (-ikaḥ)
• Oblique singular inherited from Sauraseni Apabhramsa -इहे (-ihĕ/-ihi, genitive singular), from Sauraseni Prakrit -𑀇𑀕𑀲𑁆𑀲 (-igassa) or -𑀇𑀅𑀲𑁆𑀲 (-iassa), from Sanskrit -इकस्य (-ikasya)
• Vocative singular inherited from Sauraseni Apabhramsa -इअ (-ia), from Sauraseni Prakrit -𑀇𑀕 (-iga), from Sanskrit -इक (-ika)
• Direct plural inherited from Sauraseni Apabhramsa -इअ (-ia), from Sauraseni Prakrit -𑀇𑀕𑀸 (-igā), from Sanskrit -इकाः (-ikāḥ)

See -इयों (-iyõ) and -इयो (-iyo) for the etymologies of those endings specifically. [1]

-ई • (-ī) m

1. suffix for some masculine nouns

All forms are ultimately from Sanskrit -इका (-ikā). Specifically,

• Direct singular inherited from Sauraseni Apabhramsa -इअ (-ia), from Sauraseni Prakrit [Term?], from Sanskrit -इकाः (-ikāḥ, nominative singular)
• Oblique singular inherited from Sauraseni Apabhramsa -इहे (-ihĕ/-ihi), from Sauraseni Prakrit [Term?], from Sanskrit -इकायाः (-ikāyāḥ, genitive singular)
• Vocative singular inherited from Sauraseni Apabhramsa -इए (-iĕ), from Sauraseni Prakrit [Term?], from Sanskrit -इके (-ike, vocative singular)

See -इयाँ (-iyā̃), -इयों (-iyõ), and -इयो (-iyo) for the etymologies of those endings specifically. [2]

-ई • (-ī) f

1. suffix for many feminine nouns

Inherited from Sauraseni Prakrit -𑀇𑀅 (-ia), from Sanskrit -इक (-ika, diminutive suffix) or Sanskrit -ईय (-īya, adjectival suffix).

-ई • (-ī) (Urdu spelling ـی‎)

1. relating to, forms adjectives from nouns

   ‎पहाड़ (pahāṛ, “mountain”) + ‎-ई (-ī) → ‎पहाड़ी (pahāṛī, “mountainous”).

Borrowed from the nominative singular form of Sanskrit -इन् (-in, “doer, possessor”).

-ई • (-ī) m (Urdu spelling ـی‎)

1. doer, possessor

   ‎सुख (sukh, “happiness”) + ‎-ई (-ī) → ‎सुखी (sukhī, “happy, possessing happiness”)

   ‎यात्रा (yātrā, “travel”) + ‎-ई (-ī) → ‎यात्री (yātrī, “traveller”)

Borrowed from Persian ـی‎ (-i), from Middle Persian -yk' / 𐭩𐭪𐭩‎ (yky /-īg/) or Arabic ـِيّ‎ (-iyy) or directly from Arabic ـِيّ‎ (-iyy, nisba suffix).

-ई • (-ī) f (Urdu spelling ـی‎)

1. forms abstract nouns from adjectives or common nouns

   ‎दोस्त (dost, “friend”) + ‎-ई (-ī) → ‎दोस्ती (dostī, “friendship”)

   ‎बेवक़ूफ़ (bevqūf, “foolish”) + ‎-ई (-ī) → ‎बेवक़ूफ़ी (bevqūfī, “foolishness”)