Many adjectives are formed by adding a certain ending, or suffix to a base noun or verb.

For example, “logical” is formed using the base noun “logic” and the suffix “al”.

“Washable” is created with the base verb “wash” and the suffix “able”.

These combinations are very common in English. In each case, there is almost always only one correct combination. This means it is generally not possible to creatively form other adjectives using the different suffixes, even if they have similar meanings.

To help you learn the correct suffixes to use, let’s see how they correspond with different groups of adjectives.

-al/-ial/-ical

This suffix is usually attached to base nouns. The adjective will describe being related to the noun or having similar qualities.

Examples: coastal, social, magical

-able/-ible

These suffixes describe capability of or tendency to act in a certain way. The suffix "-able" is most commonly attached to base verbs, while "-ible" can be added to base nouns or verbs.

Examples: wearable, responsible.

-an/ian

This suffix may describe belonging to a particular time, place, community, or profession. It may also describe following a set of ideas or the example of a particular person. It is usually added to base nouns, including proper nouns.

Examples: Elizabethan, Christian

-ary/-ory

This suffix is added to base nouns. It may describe the manner of doing an action or how an event occurs. The adjective may also describe being related to the noun or having similar qualities.

Examples: momentary, secondary, introductory, satisfactory

-ful

This suffix is attached to base nouns. It describes having or being full of a quality or emotion.

Examples: colorful, hopeful

-ic

This suffix is attached to base nouns. The adjective describes being related to the noun or having similar qualities. One common usage is with academic subjects, to describe aspects related to that genre or field of study.

Examples: linguistic, scientific, historic (different meaning from historical), melodic

-ive

This suffix is added to base nouns. The adjective may describe the tendency to act in a certain way. It may also describe the manner of doing an action or how an event occurs.

Examples: attractive, defensive, effective

-ish

This suffix is attached to base nouns. The adjective may describe qualities that originate from or are related to the noun. It may also be used creatively, meaning by inventing new words, to describe when there is vague similarity to or a small amount of a quality present. Creative forms are not standard and may require a hyphen.

Examples: selfish, girlish, yellowish, apple-ish

-less

This suffix is attached to base nouns. It describes the absence of a quality or ability.

Examples: careless, fearless, powerless

-like

This suffix is added to base nouns. The adjective describes having similarities to or qualities of the base noun.

Examples: childlike, lifelike

-y

This suffix is added to base nouns. The adjective may describe a tendency to act in a certain way or for a certain event to occur. It may also be used creatively, meaning by inventing new words, to describe when there is vague similarity to or a small amount of a quality present.

Example: noisy, dreamy, fishy

-ous/ose

These suffixes are attached to base nouns. The adjective may describe being related to the base noun or being full of similar qualities.

Example: ridiculous, adventurous, victorious, verbose, favose

-ent/-ant

These suffixes are attached to base verbs. The adjective describes doing an action or being in a state related to the base verb.

Example: dependent, divergent, important, defiant

-ile

These adjectives describe the tendency to act in a certain way or having similar qualities to the noun. This suffix is added to base nouns. Many of the adjectives ending in "ile" do not have recognisable base forms.

Example: infantile, fragile

Transforming the Base

The base of the adjective is the original noun or verb to which the suffix is attached. In many cases, the base is visible and easy to recognise.

Examples: wonderful, rainy, hopeless

However, this is not always the case. In fact, it is common for the base to change when the suffix is added. These changes can be minor, such as the loss or addition of a few letters. These changes are usually due to systematic spelling rules, such as the final y becoming an i before a suffix.

Examples:

mystery > mysterious

athlete > althetic

ridicule > ridiculous

In other cases, the base may need more significant transformation to form the adjective. When this happens, it can be very difficult to identify the base.

Examples:

fragment> fragile

sense > sensitive

society > social

Non-English Bases

Many adjectives formed in this way have either come directly from other languages or been strongly influenced by them. Latin and related languages are a common source of these forms. Because the structures of these adjectives were taken from other languages, they may not have an English base form.

Examples: culpable, flammable, important

Adjectives That Can't be Backformed

The currently correct forms of these adjectives have been established in different ways and at different times in history. The information on this page helps you learn how to structure the adjectives correctly using a base word and a suffix.

Logically, this would mean it is also possible to remove the suffix to find the base word.

Examples:

beautiful > beauty

adventurous > adventure

Removing the suffix to leave the base is called backforming.

However, there are many adjectives that cannot be backformed. Even if an adjective has a familiar suffix, removing the suffix can create an incorrect word.

Examples:

incessant > incess

silly > sill

independent > independ

There are many adjectives formed with suffixes, and it can be difficult to guess the single correct form each time. The good news is that some of these adjectives are very commonly used. Constant use makes it possible to learn them and remember them.