ADJECTIVE GROUPS
Latin nouns are either masculine, feminine or neuter. Because adjectives can describe all those types of noun, each adjective must have masculine, feminine and neuter forms. This sounds much more complicated than it is. If you know the noun declensions, Latin adjectives won’t give you much trouble.
Adjectives fall into two main groups. One is based on nouns of the first and second declensions. These adjectives have masculine, feminine, and neuter forms corresponding to the nouns like amicus, rosa, and donum. (There are some minor variations in adjectives like pulcher, but they soon start to feel intuitive.)
The second group of adjectives takes its forms from nouns in the third declension like ciuis. These adjectives have a shared masculine and feminine form (e.g. fortis) and a neuter form (forte). Again there are some minor variations here: adjectives like acer, acris, acre (with a distinct feminine nominative singular form) and potens (with a shared form for masculine, feminine, and neuter nominative singular). These too will soon come naturally.