Translation guide
Expressing that an action is done without thinking, carelessly, or without consideration for consequences or others' feelings.
Describing an action done automatically, without conscious thought, often leading to a mistake or unintended result.
Adverb meaning 'carelessly', 'inadvertently', or 'without thinking'. Used for accidental mistakes or forgetting.
I thoughtlessly forgot about the appointment.
I made a careless mistake.
Adverb meaning 'unintentionally' or 'without thinking', often used when you do something you know you shouldn't.
I thoughtlessly ate too much.
I inadvertently told the secret.
Adverb meaning 'casually', 'without much thought', or 'unintentionally'. Implies doing something without deep consideration.
A thoughtless remark I made casually hurt him.
Adverb meaning 'unconsciously' or 'without awareness'. Used for actions done automatically, without conscious thought.
I have a habit of thoughtlessly touching my hair.
Adverb meaning 'absentmindedly' or 'vaguely'. Used when someone is not paying attention and acts without thinking.
I was spacing out and thoughtlessly missed my stop.
Acting in a way that disregards other people's feelings or the consequences of one's actions.
Adverb meaning 'rashly', 'thoughtlessly', or 'without due consideration'. Often used for actions that are imprudent or inconsiderate.
I made a thoughtless remark and made her angry.
You shouldn't act thoughtlessly.
Adverb meaning 'insensitively' or 'thoughtlessly'. Emphasizes lack of consideration for others' feelings.
He says thoughtless things.
Phrase meaning 'without thinking' or 'thoughtlessly'. Directly expresses lack of consideration.
If you act thoughtlessly, you'll fail.
Formal adverb meaning 'thoughtlessly' or 'without deliberation'. Used in written or formal contexts.
I regret speaking thoughtlessly.
Doing something by rote or habit, without engaging the mind.
Adverb meaning 'mechanically' or 'automatically'. Used when actions are done without thought, like a machine.
I did the work thoughtlessly, like a machine.
Phrase meaning 'by force of habit' or 'through inertia'. Implies continuing without thought.
I thoughtlessly kept watching TV out of habit.
うっかり is for accidental mistakes or forgetting (e.g., forgetting an appointment). つい is for doing something you know you shouldn't but can't resist (e.g., eating too much). Both mean 'thoughtlessly' but in different contexts.
I carelessly forgot my wallet.
I end up thoughtlessly eating sweets.
Direct translations like '思考なしに' are unnatural. Use the adverbs and phrases above depending on whether the thoughtlessness is accidental, insensitive, or habitual.