Translation guide
Describes actions, words, or people lacking consideration for others or done without thinking. Japanese has distinct words for 'inconsiderate/rude', 'careless/absent-minded', and 'without deep thought'. The best choice depends on whether the focus is on hurting others, making a mistake, or acting on impulse.
Describing a person, remark, or action that lacks consideration for others' feelings, often causing hurt or offense.
Literally 'lacking consideration/thoughtfulness'. A common, natural phrase for describing someone or their actions as thoughtless in the sense of being inconsiderate.
彼の思いやりがない発言に傷ついた。
I was hurt by his thoughtless remark.
Literally 'insensitive'. Describes a person or behavior that is tactless, thick-skinned, or oblivious to others' feelings. Very common for 'thoughtless' in the sense of being rude or insensitive.
無神経なことを言ってしまった。
I said something thoughtless.
A more formal expression meaning 'lacking consideration'. Suitable for written or formal contexts.
その計画は周辺住民への配慮に欠けている。
The plan is thoughtless toward the local residents.
Means 'not thoughtful/attentive' in the sense of failing to notice what needs to be done or what others want. Often used for minor lapses in consideration.
気が利かなくてすみません。
Sorry for being thoughtless.
Describing an action or mistake made without proper attention, often resulting in an error or accident.
An adverb/na-adjective meaning 'carelessly', 'absent-mindedly', or 'without thinking'. Used for minor mistakes or forgetting things. Very common.
うっかりして電車を乗り過ごした。
I thoughtlessly missed my train stop.
うっかりミスをしてしまった。
I made a thoughtless mistake.
Means 'rash', 'hasty', or 'thoughtless' in the sense of acting without due care. Often used for serious errors in judgment.
Describing an action, statement, or decision made without careful consideration or deliberation; superficial.
Literally 'without thought'. A straightforward, slightly blunt way to say someone acts without thinking. Often used critically.
考えなしに返事をしてしまった。
I replied thoughtlessly.
Means 'shallow', 'superficial', or 'thoughtless' in the sense of lacking depth or foresight. Often used for plans or ideas.
浅はかな考えで行動すると失敗する。
If you act on a thoughtless idea, you'll fail.
A phrase meaning 'without thinking deeply'. Used to describe doing something casually or impulsively.
深く考えずにその仕事を引き受けた。
I thoughtlessly accepted the job.
思いやりがない focuses on lack of empathy or kindness. 無神経 emphasizes insensitivity to others' feelings. 考えなし is more about acting without thinking at all, not necessarily about hurting others. Choose based on whether the thoughtlessness is about being unkind, oblivious, or simply unreflective.
The English word 'thoughtless' covers a wide range. Direct translations like 思考がない (shikou ga nai) are unnatural. Use the options above based on the specific nuance.
軽率な行動で信用を失った。
I lost trust due to my thoughtless actions.
An i-adjective describing a person who is habitually careless, scatterbrained, or prone to making thoughtless mistakes.
彼はそそっかしいから、よく物をなくす。
He's thoughtless, so he often loses things.