Translation guide
This guide covers how to express 'become weak' in Japanese, focusing on physical strength, intensity, influence, and abstract qualities. It includes common verbs, adjectives, and set phrases, organized by the type of weakness.
Describing a person, animal, or body part losing physical power or stamina.
The most general and neutral way to say 'become weak' physically. Uses the adjective 弱い (weak) + なる (become).
年をとると、体力が弱くなる。
As you get older, your physical strength becomes weak.
My legs became weak due to illness.
Often used for a gradual decline in strength, especially due to age or illness. More formal/literary than 弱くなる.
祖母の足腰が衰えてきた。
My grandmother's legs and lower back have become weak.
Intransitive verb meaning 'to weaken' or 'to become weak'. Often implies a noticeable decline in condition.
暑さで犬が弱っている。
The dog is becoming weak from the heat.
Describing a force, signal, light, sound, or effect losing strength.
Works for many non-physical strengths: wind, light, sound, signal, etc.
風がだんだん弱くなってきた。
The wind is gradually becoming weak.
電波が弱くなった。
The signal became weak.
Intransitive verb meaning 'to weaken' or 'to abate'. Often used for wind, rain, or force.
台風の勢力が弱まった。
The typhoon's strength weakened.
Describing a person, group, or country losing power, authority, or influence.
Means 'to weaken' in terms of organizational strength or power. Often used in news or formal contexts.
その政党は弱体化している。
That political party is becoming weak.
Literally 'power becomes weak'. A straightforward way to say influence or strength is declining.
組合の力が弱くなった。
The union's power became weak.
Describing a weakening of resolve, will, memory, or other intangible attributes.
Can be used with abstract nouns like 意志 (will), 記憶 (memory), etc.
彼の意志が弱くなった。
His will became weak.
Means 'to fade' or 'to become dim'. Used for memories, consciousness, or feelings losing intensity.
記憶が薄れてきた。
My memory is becoming weak/fading.
Describing currency, market, or economic strength declining.
Used for currency or market strength.
円がドルに対して弱くなった。
The yen became weak against the dollar.
Specifically for prices or values falling. More technical.
株価が下落して、市場が弱くなった。
Stock prices fell and the market became weak.
弱くなる is the most versatile and neutral. 衰える implies a gradual decline, often due to age or illness, and is slightly formal. 弱る focuses on a noticeable state of weakness, often temporary.
年で体力が衰える。
Physical strength declines with age.
暑さで犬が弱っている。
The dog is weakened by the heat.
English 'become weak' often maps to adjective + なる (弱くなる) or specific intransitive verbs. Using a single verb like 弱る may not fit all contexts. Pay attention to what is becoming weak.