伝染性の
densensei no
The Japanese word for "contagious" is 伝染性の (densensei no).
伝染性の is used to describe a disease that is easily transmitted to others. It is most commonly used when followed by a noun such as 病気 (disease) to specify what is contagious.
Meaning: of a disease, easily transmitted to others (adj)
What does it mean word for word?
The word is built from the noun 伝染性 (contagiousness/infectiousness), which is composed of 伝 (transmit), 染 (stain/dye) and 性 (nature/property).
Which one should you use?
While 伝染性の focuses specifically on the transmission of a disease, the term 感染性の is a more common modern term used in medical contexts to describe infectiousness.
How does it change in a sentence?
To use the noun 伝染性 as an adjective that modifies a noun, you must include the particle の. This turns the phrase into 伝染性の.
How do you pronounce it?
densensei no
Did you know?
- The word 伝染 is often used in the phrase 伝染病 ('contagious disease'), which in early 20th-century Japan carried a heavy social stigma of impurity, reflecting ancient Shinto views on sickness.
- If you want to say something is 'infectious' or 'contagious' in a casual, non-medical way, such as a person's laughter, you would use the word うつる (utsuru) instead.
- The character 染 in 伝染性 literally means 'to dye' or 'to stain', implying that a disease 'stains' or spreads across a person like color in fabric.
Examples in context
- 新しいウイルスは非常に感染が早いです。This new virus is highly contagious.
- この病気は非常に伝染性の高いものです。Kono byōki wa hijō ni densensei no takai mono desu.This disease is highly contagious.
- 伝染性の疑いがある場合は隔離が必要です。Densensei no utagai ga aru baai wa kakuri ga hitsuyō desu.Isolation is necessary if there is a suspicion of being contagious.
- それは伝染性のウイルスによる症状ですか？Sore wa densensei no uirusu ni yoru shōjō desu ka?Are those symptoms caused by a contagious virus?
Example conversation
Kenta and Yui are talking about a health warning at school.
- 健太 Kenta結衣、新しいインフルエンザは伝染性の高いらしいよ。Yui, atarashii infuruenza wa densensei no takai rashii yo.Yui, I heard the new flu is highly contagious.
- 結衣 Yuiえっ、本当に？気をつけてなきゃね。E', hontō ni? Ki o tsuketenakya ne.What, really? We have to be careful.
- 健太 Kentaうん。手洗いをしっかりしよう。Un. Tearai o shikkari shiyō.Yeah. Let's wash our hands thoroughly.
- 結衣 Yuiそうだね。健太も無理しないでね。Sō da ne. Kenta mo muri shinaide ne.You're right. Kenta, don't overdo it either.
Sources
- Wiktionary, “contagious” translations, CC BY-SA 4.0, dump of 2026-09-26.
