Adjectives: formation
Adjectives are words that describe nouns. We can make adjectives by adding prefixes and suffixes.
Suffixes go on the end of words. They change a word from one part of speech, such as a noun or a verb, to another, such as an adjective.
For example, if you add ‘-able’ to ‘solve’, you create the adjective ‘solvable’.
- They told me the problem was not solvable, but I thought it was easy.
- The professional secretary was very helpful. She immediately understood what I needed.
The word ‘professional’ comes from ‘profession’, and ‘helpful’ comes from ‘help’.
The most common adjective suffixes and their meaning:
| Suffix | Meaning | Examples |
| -able/-ible | Worth, ability | Solvable, accessible, believable, reliable |
| -al, -ial, -ical | Quality, relation | Professional, structural, national, legal |
| -ent/-ant | Having a certain quality | Important, dependent, relevant |
| -ed | Having the quality of | Bored, interested, fascinated |
| -ic | Quality, relation | Generic, archaic, idealistic, historic |
| -ing | Referring to an activity | Boring, interesting, fascinating |
| -ish | Having the character of, about, almost | Newish, reddish |
| -ful | Having a characteristic | Helpful, colorful, useful |
| -less | Without, missing | Worthless, careless, useless, hopeless |
| -ous | Having the quality of, relating to | Adventurous, courageous, advantageous |
| -ive | Having the quality of | Festive, cooperative, sensitive |
| Note: Some words can be two parts of speech. This is true for words that end in ‘-ed’ and ‘-ing’, such as ‘bored’ and ‘boring’. In the first and third sentences below, the words are verbs, while in the others they are adjectives. In the second sentence, ‘bored’ describes the person ´I´, and in the last sentence ‘boring’ describes the word ´subject´. |
- His lecture bored the class so everyone fell asleep.
- I was so bored in his class that I fell asleep.
- You are boring me with all this information about insects.
- This is a very boring subject.
Prefixes go at the beginning of words.
The most common adjective prefixes and their meaning:
| Prefix | Examples | Meaning |
| il-, im-, ir-, in- | Not/opposite of | Illegal, Illegible, imperfect, impolite, irrelevant, irrational, inconvenient, inactive |
| un- | Unusual, unhappy, uninterested, unpleasant | |
| dis- | Dishonest, disloyal, dissimilar, disabled | |
| ultra-, super-, -hyper- | Extreme | Ultra-compact, ultrasound, hyperactive |
| inter- | Between | International, interdisciplinary |
| trans- | Across | Transatlantic, transmarine |
- I cannot read anything she writes; her writing is illegible.
- Companies don’t like to work with dishonest employees.
Spelling rules for il-, im-, ir-, in-
- Use ‘il-’ for words starting with ‘l’, such as legal (illegal) and legible (illegible).
- Use ‘ir-’ for words starting with ‘r’, such as relevant (irrelevant) and rational (irrational).
- Use ‘im-’ for words starting with ‘m’ or ‘p’, such as mature (immature) and polite (impolite).
- For other adjectives, use ‘in-’, such as convenient (inconvenient) and active (inactive).
| Note: Not all prefixes can go on all words, so it is important to use your dictionary to help you learn which prefixes are used with which words. |