Like English, Latin uses adjectives to modify or characterize nouns and pronouns. However, as an inflected language, Latin adjectives must agree with the nouns they modify in case, number, and gender. Often, a noun and its adjective have the same form and appear next to one another in a sentence. However, as with most things in Latin, there are exceptions making it impossible to rely on this convention to identify a noun and its modifying adjective.
Latin adjectives can be categorized into two major groups. Group One consists of adjectives of the first and second declension. Recall that the first declension is normally associated with the feminine gender because the great majority of its nouns are feminine. Early in most Latin programs, students are introduced to their first exception of Latin; not all first declension nouns are feminine. For example, those nouns of the first declension that identify an occupation that was traditionally held by a man are masculine. Some of the more common examples include:
Group One adjectives typically follow a very regular pattern. One of the first encountered by Latin students is the adjective “magnus, –a –um." Notice that the masculine form “magnus" is given first followed by the feminine “–a" and neuter “–um" endings. This convention is used in most Latin study programs.
To form all of a declension’s cases, you need only identify the adjective’s stem and add the appropriate ending. “Magnus" declined in all of its cases, numbers, and genders follow the patterns already learned while declining nouns. For example:
nom. magnus, magna, magnum
gen. magni, magnae, magni
dat. magno, magnae, magno
acc. magnum, magnam, magnum
abl. magno, magna, magno
nom. magni, magnae, magna
gen. magnorum, magnarum, magnorum
dat. magnis, magnis, magnis
acc. magnos, magnas, magna
abl. magnis, magnis, magnis
However, recall that an adjective must agree with the noun it modifies in case, number, and gender. Notice that this does not mean its form must be identical as well. The nouns of the first declension that are masculine (e.g. nauta, poeta) take an adjective in the masculine, not feminine, form. To write the phrase “the large sailor", the following form is correct:
Notice that although “nauta" ends with an “a", its adjective must agree in case, number, and gender. The “–us" ending is associated with the masculine gender and is, therefore, the appropriate ending for the masculine noun “nauta." This fact gives many beginning Latin students trouble because they often forget to memorize the gender of all Latin words. Although the first declension is often associated with the feminine gender, exceptions to the rule make this association irrelevant to the beginning Latin student.
Also worth noting are those Group One adjectives that end in “–er." Sometimes the “–e" is dropped and sometimes it is not. The adjective “miser" does not drop its “–e"; its stem is the entire word “miser–." “Pulcher" on the other hand drops its “–e"; its stem is “pulchr-." These facts illustrate the need to memorize the genitive form of all adjectives. All good Latin study programs reiterate this fact repeatedly at the beginning of their pedagogy. Memorization now saves the Latin student when the language becomes much less forgiving in later study.