にくい — Hard To Do

Meaning & Usage

The grammar pattern にくい (nikui) expresses that an action is inherently difficult or hard to perform. It attaches directly to the verb stem — the base form of a verb that you obtain by removing ます from the polite ます-form. The resulting expression functions as an い-adjective. That means it can modify nouns, appear predicatively at the end of a sentence, and conjugate into past, negative, and other forms just like any standard い-adjective.

Think of にくい as the Japanese equivalent of hard to [verb] or difficult to [verb] in English. Just as you might say "This pen is hard to write with" or "This road is difficult to walk on," in Japanese you say このペンは書かきにくいです and この道みちは歩あるきにくいです.

にくい describes a quality of the object or situation itself — not the speaker's personal ability. If you say この本ほんは読よみにくい, you are saying the book is hard to read — perhaps because of small print, dense vocabulary, or poor formatting — not that you personally struggle with reading. This is what separates にくい from 苦手にがて (nigate), which describes personal discomfort or weakness with something.

You will find にくい constantly in everyday conversation — describing objects, places, foods, textures, handwriting, and speech that are inherently tricky to deal with. It works equally well in casual and polite speech, and appears naturally in both written and spoken contexts. In formal or literary writing, you may encounter がたい (gatai) instead. It carries heavier emotional weight, suggesting something is near-impossible rather than merely difficult. For N5 purposes, にくい is all you need.

Because にくい functions as an い-adjective, it follows standard い-adjective conjugation rules. The negative form is にくくない (nikukunai), the past form is にくかった (nikukatta), and the past negative is にくくなかった (nikukunakatta). You can also produce the te-form にくくて (nikukute) to link two clauses. Once you know these four forms, you can use にくい in almost any context.

The natural counterpart to にくい is やすい (yasui), meaning easy to do. The two patterns work as a matched pair: 読よみにくい (hard to read) versus 読よみやすい (easy to read). Study them together — knowing both will immediately widen what you can express.

Structure & Formation

The formation of にくい is straightforward once you know how to find the verb stem (also called the ます-form base or 連用形). Take any verb, conjugate it into polite ます-form, and then remove ます. What remains is the verb stem. Attach にくい directly to it — no additional particles or changes are needed.

Basic Pattern: Verb (dictionary form) → Verb Stem (ます-form minus ます) + にくい

Conjugation of にくい (behaves as an い-adjective):

にくい can also be placed before a noun to modify it, exactly like any い-adjective: 読よみにくい本ほん (a book that is hard to read), 歩あるきにくい道みち (a road that is hard to walk on). Treat the entire compound — verb stem plus にくい — as a single adjective unit placed directly before the noun.

Example Sentences

Everyday Objects

Language Learning

Food and Eating

Places and Situations

Conjugated and Extended Forms

Common Mistakes

Mistake 1: Attaching にくい to the Dictionary Form

❌ この本ほんは読よむにくいです。

✅ この本ほんは読よみにくいです。

This is the most common error beginners make. にくい must attach to the verb stem — the form you get by removing ます from the polite ます-form. The verb 読よむ (yomu) becomes 読よみます in polite form, so its stem is 読よみ (yomi). Always conjugate to ます-form first, drop ます, then add にくい. Never attach にくい to the plain dictionary form ending in う, く, す, る, etc.

Mistake 2: Attaching にくい to an Adjective

❌ この問題もんだいは難むずかしいにくいです。

✅ この問題もんだいは分わかりにくいです。

にくい can only attach to verb stems — never to adjectives. To say a problem is hard to understand, use the verb 分わかる (wakaru → 分わかり) with にくい: 分わかりにくい. Similarly, use 使つかいにくい (verb: 使つかう) rather than trying to attach にくい to 不便ふべん or another adjective.

Mistake 3: Forgetting the い-Adjective Conjugation Rules

❌ この本ほんは読よみにくいじゃないです。

✅ この本ほんは読よみにくくないです。

にくい ends in い, so it follows い-adjective conjugation rules. To negate it, change the final い to く and add ない: にくい → にくくない. Do not use じゃない or ではない — those are for noun predicates and な-adjectives. For past tense, use にくかった, never にくいでした.

Mistake 4: Using にくい to Express Complete Inability

❌ 私わたしはピアノを弾ひきにくいです。(when meaning: I cannot play piano at all)

✅ 私わたしはピアノが弾ひけません。

にくい expresses that something is inherently difficult — challenging, but possible. It does not mean total inability. If you simply cannot play piano, use the potential negative 弾ひけません (cannot play) or できません (cannot do). Reserve にくい for the instrument itself: このピアノは弾ひきにくい (this particular piano is hard to play).

Mistake 5: Wrong Word Order When Modifying a Noun

❌ にくい読よみ本ほん ✅ 読よみにくい本ほん

When modifying a noun, the entire compound — verb stem plus にくい — appears as a single unit directly before the noun. Think of 読よみにくい as one compound adjective meaning hard-to-read, and place it in front of the noun just like any other adjective. Never separate the verb stem from にくい, and never place にくい alone at the front.

Cultural Notes

Japanese communication tends to favour softened, indirect phrasing over blunt statements. にくい fits naturally into this. Rather than 「これは間違まちがっています」(This is wrong), a speaker might say 「これは理解りかいしにくいです」(This is hard to understand) to make the same point with less friction. にくい is not just a grammar pattern — it is a small social tool for diplomatic pushback.

Product reviews are full of it. Japanese shoppers regularly reach for 使つかいにくい (hard to use), 開あけにくい (hard to open), 持もちにくい (hard to hold), and 読よみにくい (hard to read — e.g., tiny print on packaging). Read any Japanese review site and you will see these within minutes. Getting comfortable with them helps you understand reviews and write your own.

At the dinner table, food with tough textures, small bones, crumbly structures, or awkward shapes often gets described as 食たべにくい. The phrase comes up in restaurants, on cooking shows, and in ordinary family conversation. A related usage: 箸はしで食たべにくい (hard to eat with chopsticks) is a natural comment when the food just will not cooperate.

Describing someone's handwriting or speech as にくい is also a culturally accepted, softened form of feedback. 先生せんせいの字じは読よみにくいです is far less confrontational than saying the handwriting is bad. This kind of indirect framing is worth internalizing early — it reflects something fundamental about how feedback works in Japanese.

Related Grammar Points

• やすい — Easy To Do (Grammar N5)
• なる — To Become (Grammar N5)
• すぎる — Too Much / Excessively (Grammar N5)
• Past Tense of I-Adjectives — かった (Grammar N5)
• い-Adjective — Usage & Conjugation (Grammar N5)
• Negative I-Adjective: くない (ku nai) (Grammar N5)

JLPT Tips

On JLPT N5 and N4 exams, にくい most often appears in grammar selection questions where you pick the correct pattern to complete a sentence. The two most common traps: choosing between にくい and やすい, and deciding whether the verb form before にくい should be the stem (correct) or the dictionary form (incorrect).

A reliable approach: find the verb stem before you look at the answer choices. Locate the verb, conjugate it to ます-form, remove ます, and check which option attaches cleanly to that stem. Any choice showing a plain dictionary form — ending in う, く, つ, る, etc. — directly before にくい is wrong. That one check rules out many bad options fast.

Sentence transformation tasks also appear frequently. You may need to express "This book is difficult to read" using the にくい pattern. Drill common combinations until they come automatically: 読よみにくい, 書かきにくい, 聞ききにくい, 分わかりにくい, 使つかいにくい. The more of these you know cold, the faster you move through the grammar section.

Conjugation of にくい is another exam target. Questions may ask for past tense (にくかった), negative (にくくない), or past negative (にくくなかった). Review all four core forms until they feel natural — examiners deliberately test learners who forget that にくい follows い-adjective rules, not verb rules.

Finally, watch particle usage in にくい sentences. The item that is hard to do something with is typically marked by は (topic) or が (subject): この本ほんは読よみにくいです. Getting this right will help you both parse exam sentences and write accurate answers in short-answer sections.