Japanese い-Adjectives Explained: Complete JLPT N5 Grammar Guide with Examples
Master Japanese い-adjectives (i-adjectives) with clear conjugation rules, sentence patterns, and practice examples. Essential JLPT N5 grammar for beginners.
By SJA Teaching Team · Published · Updated
Japanese い-Adjectives: Everything You Need to Know (JLPT N5)
Japanese adjectives are one of the first grammar points every learner encounters. Understanding い-adjectives (i-keiyōshi) is essential for passing the JLPT N5 and building natural Japanese sentences. In this guide, we break down everything from conjugation to common mistakes.
What Are い-Adjectives?
い-adjectives are words that describe nouns and always end in one of these sounds: -ai, -ii, -ui, or -oi. Here are common examples:
- ちいさい (chiisai) – small
- おおきい (ookii) – big
- あつい (atsui) – hot
- おもしろい (omoshiroi) – interesting
- たかい (takai) – expensive / tall
How to Conjugate い-Adjectives
Unlike English, Japanese adjectives change form. Here's the conjugation pattern:
| Form | Pattern | Example (あつい – hot) |
|---|---|---|
| Present Positive | い + です | あついです (It is hot) |
| Present Negative | ~い → ~くありません | あつくありません (It is not hot) |
| Past Positive | ~い → ~かったです | あつかったです (It was hot) |
| Past Negative | ~い → ~くありませんでした | あつくありませんでした (It was not hot) |
Using い-Adjectives to Describe Nouns
Place the い-adjective directly before the noun it describes. No particle is needed!
- たかい ほん – an expensive book
- おもしろい えいが – an interesting movie
- ちいさい いぬ – a small dog
Key Rule: The describing word always comes BEFORE the noun in Japanese. This is the opposite of languages like French or Nepali in some cases.
The Special Case: いい / よい (Good)
The adjective "good" has two forms: いい and よい. Here's the important part:
- Use いい in present positive: いいです (It is good)
- Use よい for ALL other conjugations:
- よくありません (It is not good)
- よかったです (It was good)
- よくありませんでした (It was not good)
Student Tip: This is one of the most common mistakes in JLPT N5. Always remember: いい changes to よ- when conjugating!
Common Mistakes to Avoid
- Don't confuse とても with たくさん
- ✅ とても あついです (It is very hot) – とても modifies adjectives
- ❌ たくさん あついです – たくさん means "a lot" and modifies verbs/nouns, not adjectives
- Watch out for fake い-adjectives
- きれい (beautiful) looks like an い-adjective but is actually a な-adjective!
- ゆうめい (famous) also ends in い but is a な-adjective
- How to tell: these words use な before nouns → きれいな ひと (a beautiful person)
Practice Sentences
- きょうは とても さむいです。 – It is very cold today.
- この えいがは おもしろかったです。 – This movie was interesting.
- その レストランは たかくありません。 – That restaurant is not expensive.
- にほんごは むずかしいですか？ – Is Japanese difficult?
How SJA Teaches い-Adjectives
At Special Japanese Language Academy, our N5 course covers い-adjectives in Week 3-4 with:
- ✅ Pattern drills for fast conjugation mastery
- ✅ Real conversation practice using adjectives
- ✅ JLPT-style practice questions
- ✅ Mnemonic techniques to remember irregular forms
Ready to Start Learning?
📞 Phone: 015301205 / 9851049635 📧 Email: special.japanese@ymail.com 📍 Location: Kalimati, Kathmandu (Above Everest Bank)