Third-Declension Two-Termination Adjectives

A two-termination adjective has two forms in the nominative singular: one shared by the masculine and feminine, and another for the neuter. The model fortis, forte means “brave” or “strong”: fortis modifies a masculine or feminine singular noun, while forte modifies a neuter singular noun. “Two terminations” describes only this nominative pattern, not two genders and not two complete declensions.

These adjectives belong to the third declension and are regular i-stems. Their endings therefore differ from those of many nouns they modify. Unless a use is labeled otherwise, the forms and composed examples below represent unmarked Classical prose.

Recognizing the dictionary entry

A dictionary normally lists the masculine/feminine nominative and then the neuter nominative: fortis, forte “brave,” gravis, grave “heavy; serious,” levis, leve “light,” trīstis, trīste “sad,” facilis, facile “easy,” and difficilis, difficile “difficult.” The first form is not “the masculine”; it serves both masculine and feminine.

English uses the unchanged word “brave” in all three phrases. Latin makes gender visible in the nominative, but it does not mark a masculine–feminine distinction here: fortis covers both. This is a grammatical classification, not a claim that courage itself differs by gender.

The complete paradigm of fortis, forte

All three genders share the genitive, dative, and ablative forms. Masculine and feminine also share their accusatives. The neuter follows the universal rule that nominative, accusative, and vocative are identical, with plural -ia.

The three most revealing i-stem forms are ablative singular fortī, genitive plural fortium, and neuter plural fortia. Accusative plural fortīs is the inherited i-stem form; it is Classical and especially visible in conservative editions. Fortēs is also Classical and is the usual beginner production form. A poetic ablative in -e occasionally replaces -ī (literary), but fortī is the normal prose form.

The dative plural phrase mīlitibus fortibus happens to have matching endings. In praesidiō fortī, however, the second-declension noun ends in -ō and its agreeing third-declension adjective ends in -ī. Agreement means shared gender, number, and case—not shared letters.

Agreement is a dependency, not visual rhyme

To produce the adjective, first identify the noun it describes. Then determine that noun’s gender, number, and case, and select the adjective form with the same three features. Do not begin by looking for a nearby word with a similar ending.

Here legiōnem and fortem are both feminine accusative singular. Their visible endings resemble each other because both happen to use third-declension accusative -em. That resemblance is a consequence, not the rule.

Now compare two noun phrases with almost the same vocabulary:

In the first sentence, genitive plural fortium depends on mīlitum. In the second, neuter accusative singular forte depends on cōnsilium. Position helps package the contrast, but the endings reveal the underlying relationship. English relies heavily on order and the preposition “of”; Latin can place the words more freely because inflection keeps the dependencies visible.

Attributive, predicative, and focused placement

An attributive adjective forms a noun phrase with its head: mīlitēs fortēs “brave soldiers.” A predicative adjective states something about the subject, commonly with sum: mīlitēs fortēs sunt “the soldiers are brave.” The same agreement rule applies in both uses.

Latin adjective position is flexible, but not meaningless. A nearby adjective often gives a neutral, integrated description; separation or an unexpected position can add contrast, rhythm, or focus. Gravis iniūria and iniūria gravis can both mean “a serious injustice.” Context decides whether the second order makes “serious” sound more like new or contrastive information. Movement never cancels agreement.

Both trīstem and vērum modify masculine accusative singular nūntium, although trīstem comes before vērum and neither shares the noun’s final letters. Vērum belongs to a different adjective declension; adjectives agree with the noun, not necessarily with one another in surface ending.

Productive pattern and real limits

The -is, -e pattern is productive and secure for a large Classical class. Still, not every adjective that looks close belongs here. Prūdēns, prūdentis has only one nominative termination and follows the system explained on one-termination adjectives. Comparatives such as fortior, fortius look like two-termination adjectives in the nominative but are consonant stems with their own paradigm; see regular comparative adjectives.

A few adjectives fluctuate between third-declension and first/second-declension forms, including gracilis/gracilus, hilaris/hilarus, and inermis/inermus. These are lexical variants, not permission to invent an -us partner for any -is adjective. Early Latin may preserve inflectional variants (archaic), and poetic Latin occasionally uses ablative -e (literary) where ordinary prose prefers -ī. For production, use the dictionary’s Classical headword and the regular paradigm above.

Parsing and production checklist

When reading, use this order:

1. Test whether -is is nominative masculine/feminine or genitive singular; test whether -e is nominative/accusative neuter.
2. Find the possible head noun and recover its dictionary gender.
3. Check case and number from syntax, not from English word order.
4. Confirm that all three agreement features match.
5. Only then translate the phrase.

When composing, reverse the process: choose the head noun, assign its syntactic case, then decline fortis, forte independently.

Common Mistakes

1. Giving a feminine noun a first-declension-looking adjective.

2. Making the adjective imitate a second-declension noun’s ending.

3. Matching the adjective to the nearest noun rather than its head.

4. Using consonant-stem neuter plural -a.

Key Takeaways

Two-termination adjectives share one nominative singular form for masculine and feminine and use a second for neuter: fortis, forte. Their regular i-stem signatures are ablative -ī, genitive plural -ium, and neuter plural -ia. Above all, choose the adjective from its head noun’s grammatical features; matching final letters or physical proximity is never a reliable substitute for agreement.