Third Declension Adjectives

List of third declension adjectives and how to decline them.

Types of Third Declension Adjectives

  • Adjectives of 3 Endings
    • ācer, ācris, ācre
    • celer, celeris, celere
  • Adjectives of 2 Endings
    • fortis, forte
    • facilis, facile
  • Adjectives of 1 Ending
    • potēns, potentis
    • senex, senis

Forms of Third Declension Adjectives

  1. -ī in the ablative singular of all genders.
  2. -ium in the genitive plural of all genders.
  3. -ia in the nominative and accusative plural of the neuter.

Usage and Word Order

ATTRIBUTE ADJECTIVE
(Simple Modifier)
Ex: virī fortēs.

the brave men.

PREDICATE ADJECTIVE
(Describing the subject, with a form of sum or some other linking verb)
Ex: virī sunt fortēs.

the men are brave.

SUBSTANTIVE ADJECTIVE
(Used in a place of a noun)
Ex: fortūna fortēs adiuvat.

fortune helps the brave.

OBJECTIVE COMPLEMENT
(Describing the result of the action of the verb on the object)
Ex: virtūs fēcit virōs fortēs.

virtue made the men brave.

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Declension Chart

Masculine/Feminine Neuter
Nom. - -
Gen. -is -is
Dat.
Acc. -em -
Abl.
Voc. - -
Nom. -es -ia
Gen. -ium -ium
Dat. -ibus -ibus
Acc. -es -ia
Abl. -ibus -ibus
Voc. -es -ia

List of Third Declension Adjectives

Term Definition Derivatives
ācer, ācris, ācre sharp, keen, eager; severe, fierce acrid, acrimony, acrimonious, eager, vinegar
brevis, breve short, small, brief brevity, breviary, abbreviate, abridge
celer, celeris, celere swift, quick, rapid celerity, accelerate, acceleration, decelerate
difficilis, difficile hard, difficult, troublesome difficulty
dulcis, dulce sweet; pleasant, agreeable dulcify, dulcet, dulcimer
facilis, facile easy, agreeable facile, facility, facilitate
fortis, forte strong, brave fort, forte, fortify, fortitude, force, comfort
ingēns, ingentis huge -
omnis, omne every, all omnibus, bus, omnipresent, omnipotent, omniscient, omnivorous
potēns, potentis, pres. partic. of possum as an adj. powerful, mighty, strong potent, impotent, omnipotent, potentate, potential
vīrēs, vīrium, pl. f. strength vim, violate, violent
senex, senis, adj. and noun old, aged; old man senate, senator, senescent, senile, senior, seniority, sir, sire
levis, leve light; easy; slight, trivial levity, lever, levy, levee, Levant, leaven, legerdemain, alleviate, elevate, relevant, irrelevant, relieve
mortālis, mortāle mortal mortality, immortal, immortality
gravis, grave heavy, weighty; serious, important; serious, grievous aggravate, grief, grievance, grieve, grave, gravity
immortālis, immortāle not subject to death, immortal -
felīx, felīcis lucky, fortunate, happy felicitation, felicitous, infelicitous, felicity, infelicity, Felix