noun
lack of prudence; poor judgment
Refers to a person's lack of careful thought, discretion, or sound judgment. Often used in expressions like 心無しの行動 (thoughtless action).
彼の心無しの発言がみんなを傷つけた。
His thoughtless remark hurt everyone.
心無しの行動は時に大きな問題を引き起こす。
Imprudent actions sometimes cause big problems.
無分別 is a more formal term for lack of discretion or imprudence, while 心無し is a slightly more literary or expressive way to describe thoughtlessness.
軽率 is an adjective/noun meaning rash or careless, often used for actions; 心無し emphasizes the absence of considerate judgment.
Compound of 心 (heart, mind) and 無し (without), literally 'without heart/mind', used to indicate lack of thoughtful consideration.