Translation guide
The concept of moving or acting secretly to avoid detection. In Japanese, this is expressed through nouns, adjectives, and verbs that convey secrecy, covertness, and sneakiness. The most common equivalent is ステルス (suterusu), a loanword often used in technology and gaming contexts. For traditional or military stealth, 忍び (shinobi) or 隠密 (onmitsu) are used. The adjective こっそり (kossori) is the most natural way to describe doing something stealthily in everyday situations.
Referring to technology designed to avoid detection, or a mode of operation that makes something hard to detect.
Loanword from English, widely used in technical, military, and gaming contexts. Often used as a noun or in compounds like ステルス機 (stealth aircraft).
That fighter jet has high stealth capabilities.
I use stealth mode in the game.
Means 'stealthiness' or 'stealth property', used in technical descriptions.
This material has high stealth properties.
Describing an action done quietly and secretly to avoid being noticed.
Adverb meaning 'secretly', 'stealthily', or 'on the sly'. Used for everyday actions done without others noticing.
He stealthily slipped out of the room.
Noun meaning 'stealthy steps' or 'tiptoeing'. Often used with で to mean 'with stealthy steps'.
Adverb meaning 'sneakily' or 'furtively', often with a negative nuance of doing something suspicious.
Adverb meaning 'secretly' or 'in secret', more formal than こっそり. Used for planned, hidden actions.
He secretly proceeded with the plan.
Referring to the abstract quality or skill of being able to move or act without detection.
Noun meaning 'stealthiness' or 'covertness', often used in military or ninja contexts.
The stealthiness of ninjas is legendary.
Noun meaning 'stealth' or 'secrecy', often associated with ninjas or covert operations.
Noun meaning 'stealth' or 'sneaking', often used in historical or ninja contexts. Also part of 忍びの者 (ninja).
Referring to a genre of video games focused on avoiding detection.
こっそり is casual and implies doing something quietly to avoid immediate detection, often for minor personal actions. 密かに is more formal and implies a planned, hidden intention, often for significant matters.
I secretly ate the cake (so no one would see me).
I was secretly in love with her (hiding my feelings).
ステルス is a technical/gaming term. Using it for personal actions like 'I stealthily ate a cookie' would sound unnatural. Use こっそり instead.
I secretly ate some snacks.
忍び足で近づいた。
I approached with stealthy steps.
彼らはこそこそと話していた。
They were talking stealthily.
隠密行動を取る。
Take stealthy action.
Learn the art of stealth.