Translation guide
The English word 'malicious' describes actions, intent, or people that are deliberately harmful or spiteful. In Japanese, there is no single perfect equivalent; the best choice depends on whether you are describing intent, a person, an action, or software.
Describing a person's deliberate desire to harm or cause trouble.
The most direct and common way to say 'malicious' when modifying a noun. It literally means 'having ill will.'
彼は悪意のある噂を広めた。
He spread a malicious rumor.
The noun 'malice' or 'ill will.' Often used in phrases like 悪意を持って (with malice).
彼の行動には悪意が感じられた。
There was a sense of malice in his actions.
More colloquial, meaning 'mean-spirited' or 'spiteful.' Often used for petty malice.
彼女は意地悪な笑みを浮かべた。
She gave a malicious grin.
Means 'wicked' or 'evil,' implying a deeper, more sinister malice. Stronger than 悪意.
彼は邪悪な計画を企てた。
He devised a malicious plan.
Describing an action that is intentionally harmful.
Often used for malicious acts, especially in legal or formal contexts. Implies bad quality or nature.
悪質な嫌がらせが問題になっている。
Malicious harassment has become a problem.
Also works for actions, as in 'malicious act' (悪意のある行為).
それは悪意のある行為だ。
That is a malicious act.
For petty or childish malicious acts.
彼は意地悪なことをした。
He did something malicious.
Referring to malware, viruses, or harmful digital content.
The standard translation in IT contexts, as in 'malicious software' (悪意のあるソフトウェア).
悪意のあるメールに注意してください。
Please be careful of malicious emails.
The loanword 'malware' is widely understood. Use this for the noun.
そのファイルはマルウェアに感染していた。
The file was infected with malware.
Means 'unauthorized' or 'fraudulent,' often used for malicious access or programs.
不正なプログラムが検出されました。
A malicious program was detected.
Describing someone who is habitually malicious.
A straightforward way to say 'a malicious person.'
彼は悪意のある人ではない。
He is not a malicious person.
A mean or spiteful person, often in everyday situations.
あの人は意地悪な人だ。
That person is malicious.
Means 'villain' or 'bad person,' stronger and more dramatic.
悪意のある is neutral and can be used in formal or serious contexts. 意地悪な is more colloquial and often implies petty or childish malice. For cyber security, always use 悪意のある or 不正な.
The word 悪辣 (あくらつ) means 'crafty and malicious,' but it is very rare and literary. Stick to 悪意のある for most uses.
彼は悪人だ。
He is a malicious person.