-ий

• -ій (-ij) (Pre-reform orthography (1918))

From Proto-Slavic *-ьjь.

-ий • (-ij)

1. forms relational and possessive adjectives from nouns describing animals and people: -'s, -ine, -ian

   ‎соба́ка (sobáka, “dog”) + ‎-ий (-ij) → ‎соба́чий (sobáčij, “dog (relational); dog's, canine”)

   ‎ры́ба (rýba, “fish”) + ‎-ий (-ij) → ‎ры́бий (rýbij, “fish (relational); fish's”)

   ‎пти́ца (ptíca, “bird”) + ‎-ий (-ij) → ‎пти́чий (ptíčij, “bird (relational); bird's, avian”)

   ‎коза́ (kozá, “goat”) + ‎-ий (-ij) → ‎ко́зий (kózij, “goat (relational); goat's”)

   ‎лиса́ (lisá, “fox”) + ‎-ий (-ij) → ‎ли́сий (lísij, “fox (relational); vulpine, foxlike”)

   ‎стару́шка (starúška, “(little) old lady”) + ‎-ий (-ij) → ‎стару́шечий (starúšečij, “anile, like a crone or old lady”)

   ‎ча́йка (čájka, “seagull”) + ‎-ий (-ij) → ‎ча́ячий (čájačij, “seagull (relational); seagull's”) (with irregular -я-)

   ‎ко́шка (kóška, “cat”) + ‎-ий (-ij) → ‎коша́чий (košáčij, “cat (relational); cat's, feline”) (with irregular -а́-)

   ‎бог (box, “god”) + ‎-ий (-ij) → ‎бо́жий (bóžij, “god's, divine”)

   ‎деви́ца (devíca, “girl, maiden”) + ‎-ий (-ij) → ‎деви́чий (devíčij, “girl's, girlish”)

   ‎ба́ба (bába, “woman”) + ‎-ий (-ij) → ‎ба́бий (bábij, “woman's”) (pejorative or in expressions)

   ‎ребя́та (rebjáta, “children”) + ‎-ий (-ij) → ‎ребя́чий (rebjáčij, “child's, children's; childish”) (with irregular iotation)

• This suffix is added particularly to animate nouns, and has the special possessive declension. It triggers the Slavic first palatalization but not (normally) iotation; but see ребя́чий (rebjáčij) from ребя́та (rebjáta), with iotation.
• If added to reducible nouns, the noun assumes the unreduced form.

From Proto-Slavic *-ъ.

-ий • (-ij)

1. -ed

   ‎одно- (odno-, “one”) + ‎нога́ (nogá, “leg”) + ‎-ий (-ij) → ‎одноно́гий (odnonógij, “one-legged”)

   ‎жёлтый (žóltyj, “yellow”) + ‎-о- (-o-) + ‎брю́хо (brjúxo, “belly”) + ‎-ий (-ij) → ‎желтобрю́хий (želtobrjúxij, “yellow-bellied”)

   ‎без- (bez-, “without”) + ‎лик (lik, “face”) + ‎-ий (-ij) → ‎безли́кий (bezlíkij, “faceless”, literally “no-faced”)

• This suffix is a variant of -ый (-yj) used particularly after velars (к г х) due to Russian spelling rules. It is used particularly with two-part compounds, where the second part normally refers to a body part. It does not trigger the Slavic first palatalization.
• These adjectives do have short forms, of accent pattern a.

for an adjective whose stem ends in к; similarly for г and х

From Proto-Slavic *-jь.

-ий • (-ij)

1. forms adjectives from verbs, verbal nouns and compounds: -ous, -al, etc.

   ‎сход (sxod, “gathering”) + ‎-ий (-ij) → ‎схо́жий (sxóžij, “similar”)

   ‎расходи́ться (rasxodítʹsja, “to sell out”) + ‎-ий (-ij) → ‎расхо́жий (rasxóžij, “popular, in demand”)

   ‎бес- (bes-, “without”) + ‎стыд (styd, “shame”) + ‎-ий (-ij) → ‎бессты́жий (besstýžij, “shameless”)

2. forms adjectives and adjectival nouns from some nouns referring to people

   ‎возни́ца (vozníca, “charioteer”) + ‎-ий (-ij) → ‎возни́чий (vozníčij, “charioteer”)

   ‎лесни́к (lesník, “woodsman, forest ranger”) + ‎-ий (-ij) → ‎лесни́чий (lesníčij, “woodsman, forest ranger”)

   ‎рабо́та (rabóta, “work”) + ‎-ий (-ij) → ‎рабо́чий (rabóčij, “worker; worker's”)

• This suffix is not too common and appears to be formed especially from nouns and verbs ending in д. Unlike the other two suffixes, it triggers iotation.
• Adjectives formed this way tend to have a popular, colloquial flavor.

for an adjective whose stem ends in ж