Third Declension Adjectives
Just as first/second declension adjectives take their endings from first and second declension nouns, third declension adjectives take their endings from third declension nouns. There are a few exceptions to this, though. Here is a chart showing the endings for third declension adjectives.
Table 6-3 Third Declension Adjective Endings
* No predictable ending.
The differences among the forms for third declension nouns and third declension adjectives are given in bold to help you distinguish them. They largely consist of the letter i appearing in places you wouldn't have expected. The ablative singular is -ī instead of -e. The genitive plural is -ium instead of plain -um, and the neuter plural shows -ia rather than the usual simple -a. (Notice how the double neuter rule applies for adjectives, too!)
As you may recall, third declension nouns do not have any predictable endings for the nominative singular. You have to learn them by memorization. Third declension adjectives have the same quality — hence the asterisks in the chart above. Also like third declension nouns, third declension adjectives are predictable once you get past the nominative and know the stem change (if there is one). Unlike third declension nouns, however, third declension adjectives can be grouped into three types, which makes things a little easier. The groupings are determined by the number of different nominative singular forms (called terminations) an adjective has.
Remember, adjectives agree with their nouns only in gender, case, and number. Wherever third declension adjective endings vary from those of third declension nouns, that variation appears when third declension nouns and adjectives are together. “With every woman,” for instance, would be cum omnī muliere. Both omnī and muliere happen to be third declension words, but their endings don't quite look it.
Third Declension Adjectives of Three Terminations
Third declension adjectives of three terminations have three different forms for their nominative singular — one for each gender.
Table 6-4 Third Declension Adjectives of Three Terminations: ā cer,ā
In the dictionary listing ā cer,ā cris,ā cre (“sharp, fierce”), the first form, ā cer, is the masculine nominative singular, the second is the feminine, and the last one is neuter. Based on this adjective classification system, you could say that all first/second declension adjectives are adjectives of three terminations, since they all have three nominative singular forms (-us, -a, -um), a different one for the masculine, feminine, and neuter.
Third Declension Adjectives of Two Terminations
Take a look at the declension below for the adjective omnis, omne (“every,” “all”). You will notice that in the nominative singular, the masculine and feminine forms are identical and only the neuter is different. Third declension adjectives with only two different nominative singular endings are called third declension adjectives of two terminations. Their listing in the dictionary looks like this: omnis, -e.
Table 6-5 Third Declension Adjectives of Two Terminations: omnis, -e (“every,” “all”)
The first word in the dictionary listing, omnis, is the same for the masculine and feminine nominative singular. The -e part means that its neuter nominative singular is omne. Virtually all third declension adjectives of two terminations follow the pattern -is, -e in their dictionary listing.
Third Declension Adjectives of One Termination
Third declension adjectives of one termination have only one form for the nominative singular. The same form works for all three genders. The tricky part comes in the dictionary listing for them. Since third declension adjectives of one termination almost always have stem changes when they appear in any case other than the nominative singular, a dictionary can't just give you the nominative singular as it does for all other kinds of adjectives. If it did, there would be no way for you to know that the adjective ingē ns (“huge”), for example, changes to ingent- when you start putting endings on it. To get around this problem, a dictionary gives you the genitive singular form, which illustrates the stem change. Therefore, the listing for ingē ns is: ingē ns, ingentis.
Table 6-6 Third Declension Adjectives of One Termination: ingē
The first form of the dictionary listing is the nominative singular for the masculine, feminine, and neuter genders. The second form is the genitive. The sole purpose of the second word in the entry is to inform you of the stem change. With this information, you know that ingentem montem (“huge mountain”) is the accusative singular from the nominative ingē ns mī ns.
Practice with Third Declension Adjectives
Translate the following adjective/noun pairs then give their case and number. Example: omnēs mulierē s all women (acc. pl. or nom. pl.)
vitae brevē s
dominōs felicē s
vī ta fē lix
rē x senex
fē slī cis
mī litem fortem
rēs gravē s