惰性

• 読み: だせい
• ローマ字: dasei
• 漢字の分解: 惰 (da) — lazy, indolent, idle; 性 (sei/shō) — nature, tendency, inertia
• 発音: /dase̞i/

意味

Inertia; force of habit; doing something out of momentum rather than intention. Continuing a behaviour simply because it has always been done.

A formal noun. In physics it refers to inertia; in emotional and behavioural contexts it describes acting on autopilot — continuing relationships, jobs, or habits not out of will or desire but out of passive momentum. Carries a mildly negative nuance, suggesting lack of reflection or initiative. The phrase 惰性で〜する (to do something out of inertia/habit) is a common construction used in self-critical or observational speech.

例文

1. 二人の関係はすでに惰性で続いているだけで、愛情は残っていなかった。
2. 惰性で同じ仕事を続けていても、成長はない。
3. 彼は惰性でテレビを見ていたが、心はどこか遠くにあった。

使い方ガイド

場面: relationships, work, lifestyle, self-reflection

トーン: critical

起源と歴史

Compound of 惰 (da — lazy, idle, indolent) and 性 (sei/shō — nature, tendency, property). The character 性 here evokes a stable, persistent tendency — the 'nature of idleness' that keeps things moving without deliberate effort.

文化的背景

時代: Modern

世代: All ages

社会的背景: Universal