How to Form the States of Adjectives
You ask, therefore, how to tell when to use the ‑er and ‑est endings and when to use the helping words more and most? There’s no hard and fast rule, but some rules of thumb will help:
Syllable Rule for States of Adjectives
One-syllable adjectives (In almost all cases, use ‑er and ‑est.)
big, bigger, biggest small, smaller, smallest thin, thinner, thinnest
happy, happier, happiest narrow, narrower, narrowest silly, sillier, silliest
bizarre, more bizarre, most bizarre steadfast, more steadfast, most steadfast
clever, cleverer, cleverest or clever, more clever, most clever
cruel, crueler, cruelest or cruel, more cruel, most cruel
Three-syllable adjectives (Use more and most.)
difficult, more difficult, most difficult memorable, more memorable, most memorable
thrilling movie, tired golfer
Sounds-Weird Rule for States of Adjectives
Sometimes the ‑er and ‑est endings just sound strange.
For example, the correct comparative and superlative forms of common are commoner and commonest. But these words sound strange, the first like some cockney character pushing a barrow in the East End of London, the second like some sort of dangerous subversive.
Thus: common, more common, and most common would be regarded as correct by most people (simply because they’re used to hearing these forms). In formal settings, however, you should choose the correct forms, commoner and commonest.
Look-It-Up Rule for States of Adjectives
You can always find the answer in the dictionary.
Look up common, and immediately following the word you’ll find the endings ‑er and ‑est. These entries show how to form the comparative and superlative forms of the adjective.
Now look up the word different. Notice that following the entry you do not find the endings ‑er and ‑est. The absence of these endings means that you use more for the comparative and most for the superlative.
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