tsuyoi-vs-yowai

つよい (tsuyoi) and よわい (yowai) are a pair of い-adjectives that English speakers often think they know — “strong” and “weak” — but Japanese uses them in a much wider range of contexts than English. From physical strength and wind speed to personality traits, business performance, and even tolerance for alcohol, these two words are everywhere in Japanese. This guide gives you the full picture with clear examples, a comparison table, and a quick quiz.

Yuka

Quick question, Rei — when should I use つよい versus よわい?

Rei

Ah, a classic mix-up! They’re related but definitely not interchangeable. I’ll explain with examples and it’ll make perfect sense.

At a Glance: つよい vs. よわい

つよい (強い) — Strong, Powerful, and Intense

つよい covers physical strength, mental resilience, intensity of forces (wind, pain, light), and tolerance (e.g., being good at handling heat or spicy food). The kanji 強 means “strong / force.” This word appears constantly in sports commentary, weather reports, and everyday conversation.

One useful pattern is [noun] に強い — meaning “strong against / good at handling [X].” For example, 寒さに強い (samusa ni tsuyoi) means “resistant to cold” or “good at handling cold weather.”

Example 1 — physical strength:

彼はとても強い選手だ。
Kare wa totemo tsuyoi senshu da.
He is a very strong athlete.

Example 2 — wind / weather:

今日は強い風が吹いている。
Kyou wa tsuyoi kaze ga fuite iru.
There is a strong wind blowing today.

Example 3 — mental strength:

彼女は精神的にとても強い。
Kanojo wa seishinteki ni totemo tsuyoi.
She is mentally very strong.

Yuka

Oh interesting! So つよい can mean that too? I only knew the basic meaning.

Rei

Yes! つよい is more versatile than most learners realize. Native speakers use it in all sorts of situations — not just the obvious ones.

よわい (弱い) — Weak, Frail, and Mild

よわい is the direct opposite of つよい. It describes physical weakness, low intensity, frailty, and low tolerance. Just like つよい, it uses the pattern [noun] に弱い — meaning “weak against / bad at handling [X].” For example, 辛いものに弱い (karai mono ni yowai) means “can’t handle spicy food well.”

よわい can also describe a gentle, light version of something — like a weak wind or a mild flavor — so it is not always negative.

Example 1 — physical weakness:

最近体が弱くなってきた。
Saikin karada ga yowaku natte kita.
My body has been getting weaker lately.

Example 2 — low tolerance:

私はお酒に弱いです。
Watashi wa osake ni yowai desu.
I have a low tolerance for alcohol.

Example 3 — mild wind:

弱い風がそっと吹いている。
Yowai kaze ga sotto fuite iru.
A gentle breeze is blowing softly.

Yuka

What about よわい? Is it used as often as つよい in daily conversation?

Rei

よわい is super common too! The two words actually complement each other really well once you understand both.

The [Noun] に強い / に弱い Pattern

This pattern is extremely common and is one of the most useful ways to use these adjectives. It expresses what you are good or bad at tolerating or handling:

Side-by-Side Comparison

Conjugation Guide

Example using adverb form:

もっと強く押してください。
Motto tsuyoku oshite kudasai.
Please press harder (more strongly).

Decision Flowchart: つよい or よわい?

What are you describing?
        |
   ┌────┴──────────────────┐
Physical strength?     Tolerance / resistance?
   |         |              |              |
  HIGH       LOW        GOOD AT IT     BAD AT IT
   |         |              |              |
   v         v              v              v
つよい      よわい        〜に強い        〜に弱い
(強い)      (弱い)

Intensity (wind, pain, flavor)?
   HIGH → つよい  |  LOW/MILD → よわい

Quick Quiz — Test Yourself!

Yuka

Alright, I think I understand both now. Time for a quiz to check!

Rei

That’s the spirit! Testing yourself is one of the best study techniques. Ready?

Fill in the blank with つよい (強い) or よわい (弱い).

Q1. That boxer is incredibly strong.
あのボクサーはとても＿＿＿。
Ano bokusaa wa totemo ___.

Answer: つよい (tsuyoi) — 強い
Reason: A physically strong competitor = つよい.

Q2. I am bad at handling cold weather.
私は寒さに＿＿＿。
Watashi wa samusa ni ___.

Answer: よわい (yowai) — 弱い
Reason: Bad at handling cold = 寒さに弱い.

Q3. There was a strong typhoon last week.
先週、＿＿＿台風が来た。
Senshuu, ___ taifuu ga kita.

Answer: つよい (tsuyoi) — 強い
Reason: An intense/powerful typhoon = 強い台風.

Q4. The signal is too weak here.
ここは電波が＿＿＿すぎる。
Koko wa denpa ga ___ sugiru.

Answer: よわい (yowai) — 弱い
Reason: Weak signal = 電波が弱い.

Q5. She is mentally strong and never gives up.
彼女は精神的に＿＿＿、絶対に諦めない。
Kanojo wa seishinteki ni ___, zettai ni akiramenai.

Answer: つよくて (tsuyokute) — 強くて (te-form)
Reason: Mentally strong + connecting clause = te-form 強くて.

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あわせて読みたい

Continue exploring essential Japanese adjective pairs:

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