3rd Declension Adjectives

Table of contents

1. 3rd Declension Adjectives
2. 3rd Declension, 3-termination
3. 3rd Declension, 2-termination
4. 3rd Declension, 1-termination
5. Substantives

---

3rd Declension Adjectives

In the last unit, we learned that adjectives can be split into two major groups: 1st/2nd declension adjectives (otherwise known as 2-1-2s) and 3rd declension adjectives. These groupings help us understand which endings we can attach to our adjective stem to form different gender, case, and number combinations, since an adjective has to match the noun that it describes in those three aspects.

3rd declension adjectives further break down into three subgroups that can be identified from the adjective’s dictionary entry:

• 3rd declension, 3-termination
• 3rd declension, 2-termination
• 3rd declension, 1-termination

The “termination” in these subgroup titles refers to the number of endings (“termination” being from Latin terminus, -ī, m. - end) for the adjective in the nominative singular. 3-termination means that there is a distinct ending for masculine nominative singular, feminine nominative singular, and neuter nominative singular. 2-termination means that there is one ending for masculine and feminine nominative singular and another for neuter nominative singular. 1-termination means that the same form is used for all three genders, masculine, feminine, and neuter nominative singular. We’ll explore what this means below.

---

3rd Declension, 3-termination

ācer, ācris, ācre - sharp, harsh

3rd declension 3-termination adjectives have three different principal parts in their dictionary entries, but they do not follow the -us, -a, -um or -r, -a, -um pattern that we saw in 2-1-2 adjectives. Instead, the pattern is -r, -is, -e. Here are two examples:

• ācer, ācris, ācre - sharp, harsh, bitter
• celer, celeris, celere - swift, quick

As in 2-1-2 adjectives, each principal part gives us the nominative singular of each gender: for example, ācer is the masculine nominative singular form; ācris is the feminine nominative singular form; ācre is the neuter nominative singular form.

To decline a 3-termination adjective beyond the nominative case, begin the same way as with a 2-1-2 adjective: go to the feminine nominative singular form, and get the adjective’s stem by chopping off the final -is. That means that for the adjectives above, the stems are:

• ācr-
• celer-

Again, note that we need to use the feminine nominative singular form; the stem of, e.g., ācer does not use the e present in the masculine nominative singular.

Once you have your stem, then add the endings that you need. Because we’re dealing with 3rd declension adjectives, the endings will largely mirror the endings of 3rd declension nouns of the appropriate gender, but with some important differences. 3rd declension adjectives are “i-stem” substantives, which means that some of the endings will have unexpected “i”’s in them. Take a look at the following paradigm chart for 3rd declension, 3-termination adjective endings, with endings that differ from those of 3rd declension nouns in bold:

The ablative singular of all genders is -ī rather than the expected -e, and the genitive plural of all genders is -ium rather than just simply -um. In addition, the neuter nominative and accusative plural ends in -ia rather than just the expected -a. Thus, a fully-declined 3-termination adjective looks like this:

Note that the columns for masculine and feminine are largely the same, with the only difference being between the masculine nominative singular and the feminine nominative singular:

• celer equus (masc. nom. sg.) and celeris puella (fem. nom. sg.)
• but: celerī equō (masc. dat. sg.) and celerī puellae (fem. dat. sg.)

Note also how the declension of the adjective (2-1-2 versus 3rd declension) determines the possibilities for its gender, case, and number. If, for example, you didn’t know that celer, celeris, celere is a 3rd declension adjective and you thought instead that it is a 2-1-2, the -ī ending in the form celerī might lead you to expect it to be, e.g., neuter genitive singular or masculine nominative plural. This is wrong – you have to determine the adjective’s declension before parsing in order to know which chart to reference.

3rd Declension, 2-termination

3rd declension 2-termination adjectives can be recognized by the fact that their dictionary entry consists of two adjectival forms that end in -is and -e, respectively. For example:

• fortis, forte - brave, strong
• omnis, omne - (singular) each, every; (plural) all

In 2-termination adjectives, the first form (e.g., fortis) tells us the masculine AND feminine nominative singular form, while the second form (e.g., forte) is the neuter nominative singular form. Note that this type of dictionary entry consists of two principal parts, rather than three, but you can tell that it’s an adjective dictionary entry rather than a noun dictionary entry because: 1) it has no gender marker (m., f., or n.) and 2) the -e ending on the second form is not a possible genitive singular noun ending in any declension. In addition, the definition gives a word that can be used to describe a noun (e.g., ‘brave’, ‘each’) rather than giving a noun itself.

We get the stem of a 2-termination adjective from the form that ends in -is, and the stem comes from taking that -is off. Then, like 3-termination adjectives, 2-termination adjectives generally use 3rd declension noun endings except in the specific gender-case-number combinations flagged above. So, for example:

Thus:

• fortis puer templum vīdit.
  • “The brave boy saw the temple.”
• fortis puella templum vīdit.
  • “The brave girl saw the temple.”
• mater fortem fīliam mīsit.
  • “The mother sent the brave daughter.

3rd Declension, 1-termination

1-termination adjectives can be recognized by the -is ending in the second part of the dictionary entry. The first part of the entry can end in many different letters. Here are some examples of 1-termination adjectives:

• fēlix, fēlicis - lucky
• sapiens, sapientis - wise

As with 2-termination adjectives, the dictionary entry for 1-termination adjectives consists of just two principal parts, but unlike 2-termination adjectives, the form that has the ending -is is second (rather than first). This might cause confusion since 3rd declension nouns also have -is in their second principal parts, but two features can help you differentiate 1-termination adjective dictionary entries from 3rd declension noun entries: 1) 1-termination adjectives do not have a gender marker (m., f., n.), and 2) the definition indicates an adjective that can modify a noun rather than a noun itself.

In the dictionary entry for 1-termination adjectives, the first form (e.g., fēlix) signifies the nominative singular for all three genders, and the second form (e.g., fēlicis) signifies the genitive singular for all three genders. This form also gives us the stem for a 1-termination adjective once we take off the -is. The declension of a 1-termination adjective is similar to that of 2- and 3-termination adjectives and use the same endings.

The paradigm chart consists of two columns, one for masculine and feminine and one for neuter. For example:

Note the bolded form: as we learned with neuter nouns, the neuter accusative singular of a 1-termination adjective needs to be exactly similar in form to the neuter nominative singular. Thus:

• dux fēlicem virum vīdit.
  • The leader saw the lucky man.
• but: dux fēlix oppidum vīdit.
  • The leader saw the lucky town.

---

Substantives

One final note on adjectives. At times, they can be used effectively as nouns, which we refer to as substantival or substantive use of the adjective. You will recognize the substantival use of an adjective by the fact that there will be no explicit noun with which it agrees. To fill out the meaning, we can use the adjective’s gender and number to supply a word. For example, a masculine singular substantive can be expressed with the use of the word “man” or “person” (e.g., bonus, “the good man” or “the good person”). Here are some examples of nouns that you can supply based on the adjective’s gender and number:

• masculine/feminine singular: “man”, “woman”, “person”
• neuter singular: “thing”
• masculine/feminine plural: “men”, “women”, “people”
• neuter plural: “things”

See how this plays out in a few examples:

• puer bonum fēcit.
  • The boy did a good thing.
• malī oppidum reliquērunt.
  • The bad people left the town.
• puella sapientem vīdit.
  • The girl saw the wise man (or) the wise woman (or*) the wise person.

Note that for plural groups of mixed gender, Latin defaults to the masculine. So, bonī can mean either “good men”, if we know for a fact that only male-identified figures are in the group, or “good people”, if the group is of mixed gender.

One adjective of note that is often used in a substantive capacity is omnis, omne - (singular) each, every; (plural) all. It is a 3rd declension 2-termination adjective that means something different depending on whether it is singular or plural. For example:

• pater omnem librum cēpit. The father took every book.
• but: pater omnēs librōs cēpit. The father took all the books.

The substantive use of omnis can be helpfully rendered in English by the use of already-existing pronouns. For example:

• omnis templum vīdit.
  • Each person / Every person saw the temple. OR Everyone saw the temple.
• mater omnia fēcit.
  • The mother did all the things. OR The mother did everything.

---