Observe these adjectives:
We see that to express qualities above the positive degree the forms of the adjectives are changed in several ways:
Small, smaller, smallest; dry, drier, driest; slow, slower, slowest.
1. Adjectives of one syllable generally add er to form the comparative, and est to form the superlative.
Able, abler, ablest; happy, happier, happiest; polite, politer, politest.
2. Adjectives of two syllables that end in le or y, or that are accented on the second syllable, annex er to form the comparative, and est to form the superlative.
Loyal, more loyal, most loyal; important, more important, most important.
3. Most other adjectives of two syllables and adjectives of more than two syllables prefix more to form the comparative, and most to form the superlative.