Translation guide
The English word "deadly" has several distinct meanings. This guide helps learners choose the right Japanese expression depending on whether they mean "causing death," "extremely effective or accurate," "very boring or dull," or "like death in appearance."
That poison is deadly.
He made a deadly mistake.
Literally "life-taking." Often used for mistakes, habits, or decisions that prove fatal or ruinous.
That carelessness proved deadly.
Technical/medical term meaning "lethal" or "deadly." Used for diseases, doses, etc.
This is a deadly virus.
Describing a person or thing that is highly skilled, precise, or devastatingly effective, often in sports, arguments, or performance.
Can also be used figuratively to mean "devastatingly effective," especially for attacks, shots, or arguments.
His shot is deadly.
Literally "hundred shots, hundred hits." Means unerringly accurate, deadly accurate.
He is a deadly shooter.
Means "tremendous" or "immense." Can describe deadly effectiveness in some contexts.
Describing something that is so uninteresting it feels almost unbearable.
Describing a pale, ghostly, or deathly appearance, silence, or stillness.
Do not use 致命的に退屈 (chimeiteki ni taikutsu). While grammatically possible, it sounds unnatural. Use 死ぬほど退屈 (shinu hodo taikutsu) instead.
致命的 (chimeiteki) is more common and can be used for both literal and figurative deadly things. 命取り (inochitori) often implies a fatal flaw or mistake that leads to ruin, and is slightly more dramatic.
His criticism had a deadly effect.