See *-istaz.
This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.
*-ōstaz (comparative *-ōzô)
Strong declension | ||||||
---|---|---|---|---|---|---|
Case | Masculine | Feminine | Neuter | |||
Singular | Plural | Singular | Plural | Singular | Plural | |
Nominative | *-ōstaz | *-ōstai | *-ōstō | *-ōstôz | *-ōstą, -atō | *-ōstō |
Accusative | *-ōstanǭ | *-ōstanz | *-ōstǭ | *-ōstōz | *-ōstą, -atō | *-ōstō |
Genitive | *-ōstas, -is | *-ōstaizǫ̂ | *-ōstaizōz | *-ōstaizǫ̂ | *-ōstas, -is | *-ōstaizǫ̂ |
Dative | *-ōstammai | *-ōstaimaz | *-ōstaizōi | *-ōstaimaz | *-ōstammai | *-ōstaimaz |
Instrumental | *-ōstanō | *-ōstaimiz | *-ōstaizō | *-ōstaimiz | *-ōstanō | *-ōstaimiz |
Weak declension | ||||||
Case | Masculine | Feminine | Neuter | |||
Singular | Plural | Singular | Plural | Singular | Plural | |
Nominative | *-ōstô | *-ōstaniz | *-ōstǭ | *-ōstōniz | *-ōstô | *-ōstōnō |
Accusative | *-ōstanų | *-ōstanunz | *-ōstōnų | *-ōstōnunz | *-ōstô | *-ōstōnō |
Genitive | *-ōstiniz | *-ōstanǫ̂ | *-ōstōniz | *-ōstōnǫ̂ | *-ōstiniz | *-ōstanǫ̂ |
Dative | *-ōstini | *-ōstammaz | *-ōstōni | *-ōstōmaz | *-ōstini | *-ōstammaz |
Instrumental | *-ōstinē | *-ōstammiz | *-ōstōnē | *-ōstōmiz | *-ōstinē | *-ōstammiz |
This suffix was only used for regular a-stem adjectives, which sometimes used this suffix, but sometimes the related suffix *-istaz without any predictable rule. This suffix was never used for i-, u- and ja-stem adjectives.