We use comparative adjectives to compare two things, and superlative adjectives to compare three or more things. The rules for forming them depend on how many syllables the adjective has.
1. One-Syllable Adjectives
Add -er for the comparative and -est for the superlative.
- tall ➔ taller ➔ the tallest
- fast ➔ faster ➔ the fastest (If the word ends in "e", just add "-r" and "-st": large ➔ larger ➔ the largest)
2. Two-Syllable Adjectives ending in "-y"
Change the "y" to "i" and add -er or -est.
- happy ➔ happier ➔ the happiest
- busy ➔ busier ➔ the busiest
3. Long Adjectives (2+ Syllables not ending in "-y")
Use more for the comparative and the most for the superlative.
- beautiful ➔ more beautiful ➔ the most beautiful
- expensive ➔ more expensive ➔ the most expensive
4. Irregular Adjectives
These do not follow the rules and must be memorized:
- good ➔ better ➔ the best
- bad ➔ worse ➔ the worst
- far ➔ farther/further ➔ the farthest/furthest