無思慮(むしりょ)

無(む) (without) + 思慮(しりょ) (consideration, deliberation). Can function as a noun or as a na-adjective (無思慮(むしりょ)な). Describes a lack of careful thought, often with a critical nuance suggesting the person should have known better.

Common collocations

• 無思慮(むしりょ)な行動(こうどう) — thoughtless behavior
• 無思慮(むしりょ)な発言(はつげん) — thoughtless remark
• 無思慮(むしりょ)に — thoughtlessly (adverbial use)

Similar words

• 軽率(けいそつ) — rash; hasty — emphasizes acting too quickly without thinking
• 不注意(ふちゅうい) — carelessness; inattention — focuses on lack of attention rather than lack of thought
• 思慮(しりょ)深(ぶか)い — thoughtful; prudent — the positive opposite