Latin Adjectives: Third Declension

Word Endings

Third declension adjectives follow a pattern similar to how third declension nouns are declined. Furthermore, third declension adjectives can have several different terminations depending on the word. Some adjectives have three terminations (masculine, feminine and neuter), while others have two (masculine/feminine and neuter), and the rest a single termination for all genders.

Example: Three Terminations

ācer, ācris, ācre (sharp, bitter)

Singular

Case Masculine Feminine Neuter
nom. ācer ācris ācre
gen. ācris ācris ācris
dat. ācrī ācrī ācrī
acc. ācrem ācrem ācre
voc. ācer ācris ācre
abl. ācrī ācrī ācrī

Plural

Case Masculine Feminine Neuter
nom. ācrēs ācrēs ācria
gen. ācrium ācrium ācrium
dat. ācribus ācribus ācribus
acc. ācrēs/īs ācrēs/īs ācria
voc. ācrēs ācrēs ācria
abl. ācribus ācribus ācribus

Example: Two Terminations

fortis, forte (strong)

Singular

Case Masculine & Feminine Neuter
nom. fortis forte
gen. fortis fortis
dat. fortī fortī
acc. fortem forte
voc. fortis forte
abl. fortī fortī

Plural

Case Masculine & Feminine Neuter
nom. fortēs fortia
gen. fortium fortium
dat. fortibus fortibus
acc. fortēs/īs fortia
voc. fortēs fortia
abl. fortibus fortibus

Example: Single Termination

While single termination adjectives only have one termination, it’s still important to note that neuter nouns retain the nominative form when used in accusative/vocative form. This rule takes precedence over termination rules.

fēlīx (happy)

Singular

Case Masculine & Feminine Neuter
nom. fēlīx fēlīx
gen. fēlīcis fēlīcis
dat. fēlīcī fēlīcī
acc. fēlīcem fēlīx
voc. fēlīx fēlīx
abl. fēlīcī fēlīcī

Plural

Case Masculine & Feminine Neuter
nom. fēlīcēs fēlīcia
gen. fēlīcium fēlīcium
dat. fēlīcibus fēlīcibus
acc. fēlīcēs/īs fēlīcia
voc. fēlīcēs fēlīcia
abl. fēlīcibus fēlīcibus

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