An adjective modifies a noun or a pronoun and generally agrees with it in case (nominative, genitive, dative, accusative, ablative), number (singular, plural), and gender (masculine, feminine, neuter). The word generally means that there are occasionally some minor exceptions. These will be discussed later, but in general there is agreement in all three areas.

Recall that for nouns there are five declension, but each noun belongs to only one declension. The situation for adjectives is analogous: there are two groups of adjective endings, but each adjective belongs to only one group. These two groups of adjectives are called group A and group B. Group A adjectives have first and second declension endings. Group B adjectives, which are covered in lesson 6, have third declension endings. Therefore, some sources refer to group A adjectives as first and second declension adjectives, and group B adjectives as third declension adjectives. However, this can give the false impression that a particular adjective can be used with nouns of only the declension(s) its name bears. To avoid this problem, the names group A and group B are used here.

As mentioned above, group A adjectives have first and second declension endings. That is, when a group A adjective modifies a feminine noun, its ending will be one of the endings of the first declension. When it modifies a masculine noun, it will have second declension masculine endings; and when it modifies a neuter noun, it will have second declension neuter endings. Tables 4.1 and 4.2 below give the endings for group A adjectives.

Tables 4.3 and 4.4 below give the forms of the group A adjective for the English word “small”. In a glossary, the three nominative singular forms will be given. In the case of “small”, they will be parvus, parva, parvum, generally shortened to parvus, -a, -um.

-er adjectives. A few group A adjectives have a nominative singular ending of -er instead of -us. These adjectives follow the same pattern as second declension masculine nouns that end in -er. That is, sometimes the e is retained and sometimes it is dropped. For example, the group A adjective liber, libera, liberum (free) retains the e, and glaber, glabra, glabrum (glabrous) drops the e. When the e is dropped from the nominative case in the feminine and neuter forms, it is dropped everywhere else (except from the original nominative singular masculine). in the feminine and neuter forms as well as in the masculine.

Position of adjectives. An adjective generally follows the noun it modifies. For example, “a small herb” is written in Latin as herba parva. Exceptions are adjectives that denote a specific number (one, two, three, etc.) or a general quantity (e.g., few, many) and adjectives that are demonstratives (e.g., this, that). These adjectives precede the noun.
   Also, Linnaeus, in Species Plantarum, sometimes places the possessed word (in the genitive case) before the word(s) being possessed. For example, [...].

Agreement between several adjectives and a single noun. Near the beginning of this lesson, it was mentioned that there are sometimes deviations from the rule that an adjective agrees with a noun in case, number, and gender. These occur when an adjective modifies more than one noun. Let’s say, for example, that the plant you want to describe has both small leaves and small berries. The order of the words in Latin will be “with leaves and berries small”. Recall that an adjective, “small” in this example, must agree with the noun it modifies in case, number, and gender. Here both “leaves” (folia) and “berries” (baccae) are plural, so “small” needs to be plural. Also, both nouns are in the ablative case because of “with”, so “small” must also be in the ablative case. So far, so good. However, “leaves” is neuter and “berries” is feminine, so what gender do you use for the adjective? One option is to use the gender (and number and case) of he noun that is nearer to the adjective. In this example, the closer noun (“berries”) is feminine, so you can choose the feminine (ablative plural) form of “small” (parvis). Unfortunatelly, this solution does not make clear whether just the berries are small or if both the leaves and berries are small. A better colution is to use the appropriate form of small following each noun: “leaves small and berries small”.

Nine adjectives with unusual endings. Before concluding this lesson about group A adjectives, you need to about nine of these adjectives whose genitive and dative singular endings are exceptions to the endings given in the tables above. Each of these nine has an -ius ending in the genitive singular for all three genders and an -i ending in the dative singular, again for all three genders (see Table 4.5). Otherwise they follow the example of parvus, -a, -um. All nine have to do with some aspect of number. They are: