2. The Comparative is regularly formed by adding -ior (Neut. -ius), and the Superlative by adding -issimus (-a, -um), to the Stem of the Positive deprived of its final vowel; as,—

altus, high, altior, higher, altissimus, highest, very high.
fortis, brave, fortior, fortissimus.
fēlīx, fortunate, fēlīcior, fēlīcissimus.

So also Participles, when used as Adjectives; as,—

doctus, learned, doctior, doctissimus.
egēns, needy, egentior, egentissimus.

3. Adjectives in -er form the Superlative by appending -rimus to the Nominative of the Positive. The Comparative is regular. Thus:—

asper, rough, asperior, asperrimus.
pulcher, beautiful, pulchrior, pulcherrimus.
ācer, sharp, ācrior, ācerrimus.
celer, swift, celerior, celerrimus.

a. Notice mātūrus, mātūrior, mātūrissimus or mātūrrimus.

4. Five Adjectives in -ilis form the Superlative by adding -limus to the Stem of the Positive deprived of its final vowel. The Comparative is regular. Thus:—

facilis, easy, facilior, facillimus.
difficilis, diffcult, difficilior, difficillimus.
similis, like, similior, simillimus.
dissimilis, unlike, dissimilior, dissimillimus.
humilis, low, humilior, humillimus.

5. Adjectives in -dicus, -ficus, and -volus form the Comparative and Superlative as though from forms in -dīcēns, -ficēns, -volēns. Thus:—