Irregular Adjectives: Comparison Forms Explained

Irregular adjectives don't follow regular patterns with -er or -est forms. This grammar guide helps you understand their rules, differences, and real uses, with practical examples and exercises to improve accuracy for exams like IELTS, TOEIC, or daily communication.

I. What Are Irregular Adjectives in English?

In English grammar, irregular adjectives are adjectives that do not follow the standard rules when forming comparative and superlative degrees. Instead of simply adding "-er" or "-est" (as in tall → taller → tallest), these adjectives often change form entirely, or use completely different words.

Regular adjectives usually form their degrees of comparison by:

• Adding –er / –est (for one-syllable adjectives)
• Using more / most (for longer adjectives)

Irregular adjectives, however, don’t follow those patterns.

For example:

• good → better → the best
• bad → worse → the worst
• far → farther/further → the farthest/furthest

These forms must be memorized, as no predictable rule applies.

Mastering irregular adjectives improves not only grammatical accuracy, but also lexical variety—a key criterion in English proficiency assessments.

• They are commonly used in both spoken and written English.
• They appear frequently in standardized exams like IELTS, TOEIC, and Cambridge tests.
• Using them incorrectly (e.g., “more better”, “badder”) is considered a grammar mistake.

1. Common Irregular Adjectives List

Unlike most adjectives in English, irregular adjectives do not follow the typical rule of adding –er or –est to express comparison. Instead, they change form completely and must be learned individually.

Here is a list of the most common irregular adjectives:

Note: Farther is usually used for physical distance, while further is often used for abstract or figurative distance.

These adjectives are commonly used in everyday speech, exams, writing, and formal situations. Recognizing them helps avoid mistakes like “more better” or “badder”, which are grammatically incorrect.

2. Partially Irregular Forms (Both -er/-est and more/most)

Some adjectives in English are unique in that they can use both comparison forms — the “-er / -est” suffix or “more / most”, depending on context. These are often called partially irregular adjectives or flexible adjectives.

They typically have two syllables, which places them between short and long adjectives in terms of comparison rules.

Common Examples

How to Choose Between the Two Forms

Choosing between “-er/-est” and “more/most” often depends on context, formality, and naturalness in speech or writing:

Key Tip for Learners

Both forms are grammatically correct, but be consistent:

• Do not mix forms: avoid saying “more friendlier” or “most simpler”.
• Choose the version that sounds more natural and matches your tone

3. Non-Standard / Rare Irregular Forms

While most learners are familiar with common irregular adjectives like good → better or bad → worse, there are also a few non-standard or less common irregular forms in English that can cause confusion. These adjectives may appear unusual or inconsistent in how their comparative and superlative forms are constructed, so it’s important to recognize them and understand their specific usage contexts.

Ill → Worse

Ill is a less commonly used base form for the adjective sick, and its comparative form is: ill → worse (not iller)

Example:

• After traveling in winter, she felt worse each day.
• (Not: she felt iller)

Note: Ill and sick are near-synonyms in many dialects, but worse is still the correct comparative of ill when used formally.

Far → Farther / Further

The adjective far is unusual because it has two acceptable comparative and superlative forms, each used in slightly different contexts.

In modern English, farther and further are often used interchangeably, though some still maintain the physical/figurative distinction.

Old → Elder / Eldest (Context-specific)

While the standard comparative is older → oldest, there is a special comparative form used to describe family relationships: elder / eldest (used before a noun)

Examples:

• My elder brother lives abroad.
• She is the eldest of three sisters.

You cannot say “He is elder than me.” Use: “He is older than me.”

Learners aiming for more advanced grammar awareness—especially in formal writing or speaking—should be familiar with these rare but functional irregular forms. Recognizing them also helps avoid awkward or incorrect phrases such as “iller” or using “elder” in comparisons.

II. How to Use Irregular Adjectives Correctly

Understanding irregular adjectives is only the first step—knowing how to use them accurately in sentences is essential for clear, fluent, and grammatically correct communication. Whether you are preparing for academic exams or everyday conversations, correct usage

In Affirmative Sentences and Comparisons

Irregular adjectives often appear in comparative and

• Comparative Forms (comparing two things): Use the comparative form (+ than)
  Examples:
  • This phone is better than my old one.
  • He is worse at driving than his sister.
  • They traveled farther than expected.

• Superlative Forms (comparing three or more): Use the superlative form (with "the") to show the highest or lowest degree among three or more.
  Examples:
  • She is the best dancer in the group.
  • That was the worst movie I’ve seen this year.
  • This is the furthest we’ve gone in the project.

Tip: Always include “the” before superlatives with irregular adjectives (the best, the worst, the most,

In Academic Writing and Exams

Irregular adjectives are common in formal writing tasks like IELTS Writing Task 2, academic essays, and reports. Using themgrammar score and lexical resource evaluation.

Examples in formal contexts:

• Technology offers the most efficient solutions to modern problems.
• Public transport is often the least expensive option for students.
• Healthcare is better funded in urban areas.

Style guidance:

• In academic contexts, prefer precise
• Avoid conversational tone; use irregular forms to show variety and range of expression.

With practice, choosing the correct irregular form becomessome of the most frequent mistakes learners make—and how to avoid them with confidence.

III. Common Mistakes with Irregular Adjectives

Irregular adjectives do not follow standard comparison rules, so it’s no surprise that many English learners make mistakes when using them. These errors often come from overapplying regular patterns or translating too directly from one’s native language.

IV. Exercises to Practice Irregular Adjectives

The best way to master irregular adjectives is through practice. In the following exercises, you’ll identify correct forms, complete comparisons, and correct common mistakes. These activities will help reinforce the rules you've learned and improve your accuracy in both writing and speaking.

Exercise 1: Choose the Correct Form

Select the correct comparative or superlative form for each sentence.

1. This book is (good / better / best) than the one I read last week.
2. That was the (bad / worse / worst) meal I've ever had.
3. She’s feeling (ill / worse / worst) today than yesterday.
4. Who ran (far / farther / farthest) in the race?
5. This is the (more polite / politest / most polite) email I've ever received.

Exercise 2: Fill in the Blanks

Use the base adjective given in parentheses to complete each sentence with the correct comparative or superlative form.

1. John is the ________ student in our group. (good)
2. Today’s weather is ________ than yesterday’s. (bad)
3. This mountain is much ________ than I expected. (far)
4. Which city has the ________ population? (many)
5. I made a ________ mistake in my first attempt. (little)

Exercise 3: Spot and Correct the Mistakes

Each of these sentences contains a grammar mistake involving an irregular adjective. Rewrite the sentence correctly.

1. This phone is more better than the old one.
2. That’s the most worst decision we could make.
3. He felt more worse after taking the medicine.
4. She is best player on the team.
5. It was the most baddest moment of the competition.

Answer Key

Irregular adjectives are important grammar items that students must learn and memorize their different variations. But it's not as difficult as it seems if you are truly determined to master them. You just need to study the theoretical knowledge provided by PREP combined with practice exercises - that way you will certainly be able to conquer irregular adjectives.