"Adjectives can express degrees of modification:
Gladys is a rich woman, but Josie is richer than Gladys, and Sadie is the richest woman in town.
The degrees of comparison are known as the positive, the comparative, and the superlative. (Actually, only the comparative and superlative show degrees.) We use the comparative for comparing two things and the superlative for comparing three or more things. Notice that the word than frequently accompanies the comparative and the word the precedes the superlative. The inflected suffixes -er and -est suffice to form most comparatives and superlatives, although we need -ier and -iest when a two-syllable adjective ends in y (happier and happiest); otherwise we use more and most when an adjective has more than one syllable."