One way to form an adjective is to add a suffix to a noun, thereby transforming it into a modifier that can either be used before the noun to be modified, or after a static verb, such as "is" or "seems." However, there aren't any concrete rules for adding these suffixes. What we have instead are some patterns that guide us when constructing these words, patterns based upon the type of modification being implemented.

Adjectives of Relation

Certain suffixes will transform a noun into one that modifies another according to a state of being. For example, the suffix "-al" can be added to the noun "accident" to form the adjective "accidental," which will relate any noun it is paired with to the state of being an accident. Adjectives that relate a noun to a quality can also be formed by adding the suffix "-ary" or "-ous," such as constructing the adjective "honorary" from "honor," or "poisonous" from "poison."

Adjectives that Express Nature

Adjectives can also be formed that will modify a noun and express an aspect of its nature. These suffixes are: "-ic," "-ical," "-ish," and "-ous." The word "photograph" can be transformed into "photographic" simply by adding the suffix. However, some nouns require a change in spelling. "Athlete" and "base" must have the final "-e" dropped before adding the suffixes to construct "athletic" and "basic." "History" loses its "-y" before the "-ic" can be added to make it "historic."

Adjectives of Fullness

The suffix "-ful" can be added to a certain nouns to construct adjectives that express how the noun to be modified is full of the quality expressed by the adjective's root. In this way "skill" becomes "skillful" and "wonder" becomes "wonderful." However, some constructions require spelling changes: The "-y" in beauty becomes an "-i" in the transition from "beauty" to "beautiful." The "-e" in "awe" is dropped before it becomes "awful."

Adjectives that Convey Similarity

The suffixes that express how a modified noun is like the root of an adjective are "-like," "-ly," and "-y." They are placed at the end of a noun, often with no spelling changes, and transform the nouns like "child," "friend," and "rain" into "childlike," "friendly," and "rainy." Sometimes, however, slight spelling changes occur. Sometimes before adding the suffix "-y," the final consonant is doubled. In this way "fun" becomes "funny" and "spot" becomes "spotty."