〜にくい (Hard to)

What is 〜にくい?

〜にくい (nikui) attaches to verbs to express that something is difficult to do or resistant to happening. It's the opposite of やすい.

English equivalent: "hard to [verb]," "difficult to," "not easily"

Structure: [Verb ます-stem] + にくい

読む (yomu - read) → 読み + にくい = 読みにくい
"hard to read"

壊れる (kowareru - break) → 壊れ + にくい = 壊れにくい
"hard to break" / "durable"

分かる (wakaru - understand) → 分かり + にくい = 分かりにくい
"hard to understand"

Basic Formation

With verb stems

[Verb ます-stem] + にくい

読みにくい (yominikui) - "hard to read"
書きにくい (kakinikui) - "hard to write"
使いにくい (tsukainikui) - "hard to use"
分かりにくい (wakarinikui) - "hard to understand"

Difficult to Do

Actions that are challenging

この本は読みにくい。
Kono hon wa yominikui.
"This book is hard to read."

このペンは書きにくい。
Kono pen wa kakinikui.
"This pen is hard to write with."

分かりにくい説明。
Wakarinikui setsumei.
"A hard-to-understand explanation."

食べにくい形。
Tabenikui katachi.
"A hard-to-eat shape."

Resistant to Happening

Not prone to occur

壊れにくい。
Korenikui.
"Durable" / "Hard to break."

忘れにくい。
Wasurenikui.
"Hard to forget" / "Memorable."

風邪を引きにくい。
Kaze wo hikinikui.
"Not prone to catching colds."

太りにくい体質。
Futorinikui taishitsu.
"A body type that doesn't gain weight easily."

Physical Properties

Object characteristics

滑りにくい (suberinikui) - "non-slip"
壊れにくい (korenikui) - "durable"
曲がりにくい (magarinikui) - "hard to bend"
汚れにくい (yogorenikui) - "stain-resistant"
錆びにくい (sabinikui) - "rust-resistant"

この床は滑りにくい。
Kono yuka wa suberinikui.
"This floor is non-slip."

この素材は汚れにくい。
Kono sozai wa yogorenikui.
"This material is stain-resistant."

Poor Usability

Design problems

使いにくい (tsukainikui) - "hard to use" / "not user-friendly"
見にくい (minikui) - "hard to see"
持ちにくい (mochinikui) - "hard to hold"
覚えにくい (oboenikui) - "hard to remember"

使いにくいアプリ。
Tsukainikui apuri.
"A hard-to-use app."

見にくいデザイン。
Minikui dezain.
"A hard-to-see design."

Personal Characteristics

Individual tendencies

疲れにくい (tsukarenikui) - "not easily tired"
泣きにくい (nakinikui) - "doesn't cry easily"
怒りにくい (okorinikui) - "doesn't get angry easily"
緊張しにくい (kinchou shinikui) - "doesn't get nervous easily"

最近疲れにくくなった。
Saikin tsukarenikui natta.
"I don't get tired as easily lately."

彼は怒りにくい性格だ。
Kare wa okorinikui seikaku da.
"He has a personality that doesn't get angry easily."

Modifying にくい

Making it negative or past

Negative (not that difficult):

読みにくくない (yominikuku nai) - "not hard to read"
分かりにくくない (wakarinikuku nai) - "not hard to understand"

この文章は読みにくくない。
Kono bunshou wa yominikuku nai.
"This text is not that hard to read."

Past:

読みにくかった (yominikukatta) - "was hard to read"
使いにくかった (tsukainikukatta) - "was hard to use"

あの説明は分かりにくかった。
Ano setsumei wa wakarinikukatta.
"That explanation was hard to understand."

Comparing Items

More difficult

AよりBの方が読みにくい。
A yori B no hou ga yominikui.
"B is harder to read than A."

このペンの方が書きにくい。
Kono pen no hou ga kakinikui.
"This pen is harder to write with."

前より使いにくくなった。
Mae yori tsukainikuku natta.
"It became harder to use than before."

Common Expressions

分かりにくい (wakarinikui) - "hard to understand"
読みにくい (yominikui) - "hard to read"
使いにくい (tsukainikui) - "hard to use"
食べにくい (tabenikui) - "hard to eat"
壊れにくい (korenikui) - "durable"
忘れにくい (wasurenikui) - "hard to forget"
疲れにくい (tsukarenikui) - "not easily tired"
太りにくい (futorinikui) - "doesn't gain weight easily"
風邪を引きにくい (kaze wo hikinikui) - "not prone to colds"

にくい as い-adjective

Functions like an adjective

読みにくい本 (yominikui hon) - "a hard-to-read book"
使いにくい道具 (tsukainikui dougu) - "hard-to-use tools"

読みにくいです。
Yominikui desu.
"It's hard to read." (polite)

とても分かりにくかった。
Totemo wakarinikukatta.
"It was very hard to understand."

Making Things Easier/Harder

With する/なる

分かりにくくする (wakarinikuku suru) - "make harder to understand"
読みにくくなる (yominikuku naru) - "become harder to read"

文字が小さくて読みにくくなった。
Moji ga chisakute yominikuku natta.
"The text became smaller and harder to read."

説明が分かりにくくなっている。
Setsumei ga wakarinikuku natte iru.
"The explanation is becoming harder to understand."

Polite Forms

Casual: 読みにくい
Polite: 読みにくいです
Negative: 読みにくくない / 読みにくくないです
Past: 読みにくかった / 読みにくかったです

この本は読みにくいです。
Kono hon wa yominikui desu.
"This book is hard to read."

とても分かりにくかったです。
Totemo wakarinikukatta desu.
"It was very hard to understand."

Comparing にくい and やすい

Difficult vs easy

にくい - Difficult/resistant:

読みにくい (yominikui)
"hard to read"

壊れにくい (korenikui)
"hard to break" / "durable"

やすい - Easy/prone:

読みやすい (yomiyasui)
"easy to read"

壊れやすい (kowareyasui)
"breaks easily"

Pattern	Meaning	Example
にくい	Difficult/resistant	読みにくい
やすい	Easy/prone	読みやすい

See: 〜やすい (Easy to)

Expressing Discomfort

Psychological difficulty

言いにくい (iinikui) - "hard to say"
聞きにくい (kikinikui) - "hard to ask"
断りにくい (kotowariniui) - "hard to refuse"

ちょっと言いにくいんだけど...
Chotto iinikui n da kedo...
"This is a bit hard to say, but..."

聞きにくいことですが...
Kikinikui koto desu ga...
"This is hard to ask, but..."

Common Mistakes

Mistake 1: Using wrong verb form

❌ 読むにくい ✓ 読みにくい

Use ます-stem, not dictionary form.

Mistake 2: Confusing similar sounds

見にくい (minikui) = "hard to see"
醜い (minikui) = "ugly"

Different words, same pronunciation!

Mistake 3: Wrong formation with する verbs

❌ 勉強にくい ✓ 勉強しにくい

勉強する → 勉強し + にくい

Mistake 4: Using を instead of が

When describing what is difficult:

❌ この本を読みにくい ✓ この本は読みにくい ✓ この本が読みにくい

Summary

Key Points:

• にくい expresses difficulty or resistance
• Formation: [Verb ます-stem] + にくい
• Functions as an い-adjective
• Two meanings: "hard to do" and "resistant to happening"
• Common with: 読む, 使う, 分かる, 壊れる, 忘れる
• Conjugates like い-adjectives (にくい → にくくない → にくかった)
• Opposite: やすい (easy to)
• Essential for describing difficulty and durability