Translation guide
Describes someone who continues to work hard or show energy without becoming tired. In Japanese, this is often expressed through adjectives describing persistent effort, or through phrases about not showing fatigue.
To describe someone who works tirelessly and never seems to run out of energy.
Literally 'does not know fatigue'. A common and natural way to describe someone who seems tireless.
To describe an activity or effort that is carried out without stopping or losing intensity.
疲れを知らない emphasizes the lack of fatigue, while 精力的 emphasizes the presence of energy. Both can translate 'untiring', but 精力的 is more about proactive vigor.
He never seems to get tired.
He is an untiring worker.
Means 'energetic' or 'vigorous'. Often used to describe someone who tackles tasks with tireless energy.
She is active untiringly.
A literary adjective meaning 'untiring' or 'unflagging'. Often used in formal or written contexts.
His untiring efforts bore fruit.
Means 'without tiring' or 'without growing weary'. Very formal and literary.
He continued his research untiringly.
Means 'incessant' or 'unceasing'. Used for efforts or actions that continue without pause.
I was impressed by his untiring efforts.
Means 'constant' or 'unremitting'. Often used in phrases like 'untiring efforts'.
Untiring effort brings success.
He is energetic/untiring.