Grammar: Comparative and Superlative
The comparative form of adjectives (fast - faster; large - larger) is formed by adding -ior / -ius to the stem. Remember: to find the stem of a third-declension adjective, you have to use the genitive form. So the comparative of carus is carior. The comparative of audax (audacis) is audacior.
The comparative adjective form is always a third declension adjective. Here is an example of how comparative adjectives decline:
In order to express the "than" part of a comparison (Texas is bigger than Oklahoma), you have two options in Latin:
To form the superlative, add -issimus to the stem. This forms a basic first/second declension adjective. The superlative of carus is carissimus. The superlative of audax is audacissimus.
Adjectives that end in -er form the superlative with -errimus. For example: miserrimus, most wretched.
Some adjectives that end in -ilis form the superative with -illimus. For example: facillimus, most simple.
In many cases, adverbs are neuter singular adjectives. When an adverb takes the form of a neuter singular adjective, this means that the comparative form of the adverb takes the ending -ius.