Translation guide
The state or quality of not thinking about the consequences of one's actions or the feelings of others; lack of consideration or care.
Describing someone who acts without thinking about how it affects others, often causing inconvenience or hurt.
A common phrase meaning 'lacking consideration/thoughtfulness.' It directly points out the absence of empathy or care.
He is thoughtless.
Saying something like that is really thoughtless.
Literally 'insensitive,' this word describes someone who is tactless or oblivious to others' feelings. Often used for blunt or careless remarks.
I was hurt by his thoughtless remark.
What a thoughtless person.
Means 'lacking consideration/attention.' Slightly more formal, often used when someone fails to take necessary care in a situation.
His actions were thoughtless.
Means 'not attentive' or 'not quick to notice what needs to be done.' Implies a lack of thoughtfulness in anticipating others' needs.
He's thoughtless, so he never helps out.
Describing impulsive or careless behavior that leads to mistakes or problems.
Means 'rash' or 'imprudent.' Used for actions done without careful thought, often leading to negative outcomes.
You should avoid thoughtless actions.
Literally 'without thought.' A straightforward, slightly colloquial way to say someone acts without thinking.
If you act thoughtlessly, you'll fail.
Means 'indiscreet' or 'lacking judgment.' Often used for foolish or reckless behavior.
Means 'reckless' or 'foolhardy.' Emphasizes a daring, thoughtless disregard for danger.
Describing a state of not paying attention or forgetting things due to lack of thought.
An adverb/na-adjective meaning 'carelessly' or 'absent-mindedly.' Often used for minor mistakes or forgetfulness.
I thoughtlessly forgot the appointment.
Means 'vacantly' or 'absent-mindedly.' Describes a state of not thinking clearly or being spaced out.
Both describe a lack of consideration, but 思いやりがない focuses on the absence of empathy or kindness, while 無神経 emphasizes insensitivity to others' feelings or social cues. 無神経 is often used for blunt or tactless remarks.
He has few friends because he is thoughtless (lacks empathy).
Everyone fell silent at her thoughtless (insensitive) words.
The direct translation '思考の欠如' (shikou no ketsujo) is rarely used in natural Japanese. It sounds overly clinical or philosophical. Use the expressions above depending on the nuance you want to convey.
The project failed due to his thoughtless decision.
He is thoughtless.
Please refrain from thoughtless remarks.
It was a thoughtless challenge.
I make a lot of thoughtless mistakes.
ぼんやりしていて電車を乗り過ごした。
I was thoughtless and missed my train stop.