noun
Refers to a state of not being active, often used in medical or formal contexts to describe physical or mental sluggishness.
長期の不活動は筋力低下を招く。
Prolonged inactivity leads to muscle weakness.
うつ病の症状として不活動が見られることがある。
Inactivity can be seen as a symptom of depression.
停滞 implies stagnation or a halt in progress, often used for economic or social contexts, whereas 不活動 is more about a general state of not being active.
Compound of 不 (fu, 'not') and 活動 (katsudō, 'activity'). The exact historical derivation is uncertain, but the word follows a common Sino-Japanese pattern for negation.