Translation guide
The process of becoming worse in quality, condition, or value. In Japanese, this concept is expressed through various nouns and verbs depending on what is deteriorating and the context.
Expressing that something is getting worse in quality or condition over time.
The most common and general term for deterioration or worsening of a situation, condition, or quality. Used for health, relationships, weather, economy, etc.
病状が悪化した。
His condition deteriorated.
関係が悪化する一方だ。
The relationship is only getting worse.
Refers to deterioration in quality, especially of materials, products, or abilities. Often implies degradation or loss of original properties.
プラスチックが紫外線で劣化する。
Plastic deteriorates from UV rays.
バッテリーの劣化が早い。
The battery degrades quickly.
A drop or decline in level, standard, or ability. Often used for performance, quality, or function.
品質が低下している。
The quality is deteriorating.
集中力が低下した。
My concentration declined.
Describing the physical breakdown of objects, structures, or materials over time.
Deterioration due to aging, especially for buildings, infrastructure, or equipment. Implies becoming old and worn out.
橋の老朽化が問題になっている。
The deterioration of the bridge is a problem.
Corrosion or decay, often chemical or biological. Used for metals rusting, wood rotting, etc.
Wear and tear from friction. Used for mechanical parts, tires, etc.
Referring to the worsening of moral standards, culture, or society.
Decadence, degeneration, or moral decay. Often used in literary or critical contexts.
道徳の退廃が叫ばれている。
Moral decay is being decried.
Corruption or depravity, often of an individual's character or lifestyle.
Specifically about worsening health or medical conditions.
Physical weakening or debilitation, often due to illness or age.
病気で体が衰弱している。
His body is weakened by illness.
Decline or weakening, often of physical strength, mental faculties, or vitality.
悪化 (あっか) is the most general 'worsening' and can be used for almost any negative change. 劣化 (れっか) specifically means degradation in quality or performance, often of materials or skills. 低下 (ていか) is a decline or drop in level, often used for measurable things like quality, ability, or temperature.
The pipe corrosion is progressing.
The tire wear is severe.
He fell into depravity through drinking and gambling.
体力の衰えを感じる。
I feel a decline in my physical strength.