An adjective is a word that describes. Adjectives convey a sense of which, what kind, or how many/much. Adjectives describe nouns or pronouns.

Last summer I climbed that mountain. (which)

I prefer red apples. (what kind)

I want six oranges. (how many)

It was a cold, gray, and ominous dawn. (what kind)

The dawn was bright, clear, and invigorating. (what kind)

The Rosemont team is better than the Middlesboro team, but Ashland is the best team. (comparative and superlative adjectives)

Timothy is a fast runner; Harold is faster than Timothy, and Martin is the fastest runner.

The sentence immediately above displays the base adjective fast and the comparative and superlative forms of the adjective. Note that an adjective, expressed in comparative degree, is meaningless if it is not compared to something. Advertisers frequently use a comparative adjective without a comparison, e.g., Our laundry soap is better. Their laundry soap is better than what? No soap? Leaving your clothing out in the rain?

hot hotter hottest
new newer newest
pretty prettier prettiest
bright brighter brightest

Some adjectives have irregular comparative and superlative forms.

irregular adjective forms

good better best
bad worse worst
some more most

For some adjectives formation of the comparative requires the word more, and formation of the superlative requires the word most.

adjectives formed with more/most

popular more popular most popular
famous more famous most famous
gorgeous more gorgeous most gorgeous

Consult your dictionary to determine how to form the comparative and superlative versions of the adjective. Find the word new in your dictionary. It will be listed as an adjective. You will find the comparative ending (er) and the superlative ending (est) listed. Consequently, the comparative form is newer, and the superlative form is newest.

Find the word hot in your dictionary. The spelling of the comparative and superlative forms requires the (er) and the (est), but another spelling change is also required. Consequently, the comparative form is listed as hotter, and the superlative form is listed as hottest. Note the addition of a second letter (t) in the comparative and superlative forms of the adjective.

Find the word good in your dictionary. The dictionary lists good as an adjective. The comparative form is listed as better, and the superlative form is listed as best.

Find the word popular in your dictionary. It is listed as an adjective, but neither a comparative form nor a superlative form is listed. That is a clue that we must preface the comparative form with the word more and the superlative form with the word most.

Some adjectives cannot, logically, be expressed in degree, i.e., comparative or superlative. There are no degrees for infinite, perfect, unique, or pregnant.

Strangely, the word dead has comparative and superlative forms.

In English grammar the function of a word in a sentence determines the classification of the word. Some words can function in more than one classification. Consider the following examples.

Water sustains life. (noun)
Water the lawn. (verb)
He likes water sports. (adjective)

A few more examples of adjective usage are shown below.

Have you seen Orville's flying machine?
That was an inspiring lecture.
This is the ultimate analysis.

Some verbs and nouns may function as adjectives. The word fly is a verb, but when the verb is used to describe a noun as in flying machine, the verb fuctions as an adjective. Inspire is a verb, but when it is used to describe a noun as in inspiring lecture, the verb functions as an adjective.

The word compass is a noun, and the word needle is a noun. However, when nouns are employed in pairs as in compass needle, the first noun may function as an adjective that describes the second noun.

The compass needle is broken.

What kind of needle? Answer: compass—not a sewing needle. The word compass functions as an adjective that describes the needle.

Frequently used noun pairs are eventually joined to form a single word. Thus, the nouns basket and ball became basketball. The nouns base and ball became baseball, and the nouns foot and ball became football. Words so joined are called compound words. The compounded noun retains the adjectival information, e.g., the compound noun basketball describes the kind of ball. Use your dictionary to determine whether words have been compounded.

A pronoun may fuction as an adjective. The word this is a demonstrative pronoun that functions as an adjective in the following example.

I like this book.

Which book? Answer: this. The word this identifies which book I like.