forming comparatives and superlatives from adjectives
 
The rules for forming comparatives (e.g., better, more handsome, prettier) and superlatives (e.g., best, most handsome, prettiest) from adjectives are explained below. As they are quite complicated, some people form double comparatives (e.g., more better, more handsomer, more prettier) or double superlatives (e.g., bestest, most handsomest, most prettiest). These double forms are serious grammar errors.
 


The rules for forming comparatives and superlatives from adjectives are varied.

Comparatives of Adjectives

Examples:

Misty Blue is a stronger horse on the flat.
(stronger: comparative of strong)

The band must be made from a more precious metal than silver.
(more precious: comparative of precious)

Peter is far clumsier.
(clumsier: comparative of clumsy)

Try this question. It is less difficult.
(Less difficult is a comparative of difficult. However, it is common practice to
choose a word with the opposite meaning rather than use the less form. 
(e.g., less difficult = easier / less strong = weaker)

The pansies here seem less dainty than the ones at home.
(less dainty: comparative of dainty)

Superlatives of Adjectives

Geoff is now officially the strongest man in the world.
(strongest: superlative of strong)

The bill is extortionate, and this is the noisiest place I have ever stayed.  
(noisiest: superlative of noisy)

It is the least attractive offer, but we are obliged to take it.  
(least attractive: superlative of attractive)

He ranks as one of the most silly people on the planet.
(silliest: superlative of silly)

Last week, I stated that this woman was the ugliest woman I had ever seen. I have since been visited by her sister and now wish to withdraw that statement. (Mark Twain)
(ugliest: superlative of ugly)

Forming Comparatives and Superlatives from Adjectives

The table below shows the rules for forming comparatives and superlatives from adjectives:

Type of Adjective Example of Type of Adjective How to Form the Comparative How to Form the Superlative
One Syllable strong add er
stronger
add est
strongest
One Syllable Ending Vowel Consonant big
thin
double consonant and add er
bigger
thinner
double consonant and add est
biggest
thinnest
More Than One Syllable famous add less or more
more famous
add most or least
least famous
More Than One Syllable Ending y silly remove y add ier
sillier
for less
less silly
remove y add iest
silliest
for least
least silly
Irregular bad
good
many
no rules
worse
better
more
no rules
worst
best
most

 
COMPARATIVE? 

Words like prettier and richer (formed from the adjectives pretty and rich) are known as comparatives. A comparative is used to show who (or what) has a quality to the greater or lesser degree. (In the first example below, the quality being compared is height.)
You call that high? Blackpool Tower is higher. 
(higher: comparative of high)
The male fish is more beautiful than the female. 
 (more beautiful: comparative of beautiful)

SUPERLATIVE?

Words like prettiest and richest (formed from the adjectives pretty and rich) are known as superlatives. A superlative is used to show who (or what) has a quality to the greatest or least degree.
It is the most wonderful chocolate fudge I have ever tasted. 
(most wonderful: superlative of wonderful)
Adam is good, but Simon is the best. 
(best: superlative of good)
 
 
ONLY DO IT ONCE 

When forming a comparative or a superlative, be careful not to use a double comparative or a double superlative. This is a common mistake, particularly in speech.
Ann is more prettier than Carla.
(This is a double comparative. The word prettier is the comparative of pretty. It is a mistake to use the word
more as well.)
Ann is prettier than Carla.
He was the most best player.
(This is a double superlative. The word best is the superlative of good. It is a mistake to use most as well. The word 'bestest' is obviously wrong too.)
He was the best player.
Geoff was most quickest in the trials.

MORE SINGLE? 

Arguably, there are adjectives that should not have comparative or superlative forms because their meanings already express the qualities to the highest possible degree. For example:

  • Instantaneous
    (Can something be more instantaneous?)
  • Dead
    (Can something be more dead?)

Other examples are: single and unique.
 

See also:

What are adjectives?
Comparatives superlatives of adverbs
List of easily confused words