Adjective morphology rules

Adjective rules

Adjectives change their endings to indicate their number, gender and case. These will be the same as those of the noun they describe.

In the first half of your first year of Latin, you will meet first-second declension adjectives: the feminine forms of these adjectives belong to the first declension; their masculine forms belong to the second declension.

masculine form feminine form
bonus bona
miser misera

Masculine adjective rules

These are identical to the rules for changing the endings of second declension nouns.

masculine accusative singular

rule example
·us → ·um bonus → bonum
·er → ·erum miser → miserum

masculine ablative singular

rule example
·us → ·o bonus → bono
·er → ·ero miser → misero

masculine nominative plural

rule example
·us → ·i bonus → boni
·er → ·eri miser → miseri

masculine accusative plural

rule example
·us → ·os bonus → bonos
·er → ·eros miser → miseros

masculine ablative plural

rule example
·us → ·is bonus → bonis
·er → ·eris miser → miseris

Feminine adjective rules

These are identical to the rules for changing the endings of first declension nouns.

feminine accusative singular

rule example
·a → ·am bona → bonam
misera → miseram

feminine ablative singular

rule example
·a → ·a bona → bona
misera → misera

feminine nominative plural

rule example
·a → ·ae bonus → boni
misera → miserae

feminine accusative plural

rule example
·a → ·as bona → bonas
misera → miseras

feminine ablative plural

rule example
·a → ·is bona → bonis
misera → miseris