防水（ぼうすい、bousui）
- waterproof

The Japanese word 防水 (ぼうすい) means "waterproof" or "water resistance." It refers to the ability of something to prevent water from entering or damaging it. This term can describe a wide range of objects, from clothing and electronics to buildings and other structures. The level of 防水 can vary; some items are water-resistant, meaning they can withstand some water exposure, while others are completely 防水, designed to be submerged.

⚫︎この時計は防水です。 Translation: This watch is waterproof. ⚫︎防水のジャケットを着ています。 Translation: I am wearing a waterproof jacket. ⚫︎スマートフォンは防水機能が付いていますか？ Translation: Does your smartphone have a waterproof function?

You use 防水 in situations where you are describing the ability of something to resist water. It is a common term used in product descriptions, especially for items that might come into contact with water, such as outdoor gear, electronics, and clothing. You can use it to ask questions about the water resistance of an item or to state that something has this characteristic. It is often combined with other words to provide more specific information, for example, "waterproof camera" or "waterproof bag."

防水 is typically written in kanji as 防水 and its reading is ぼうすい in hiragana. There are no other common ways to write this word. The okurigana is standard.

⚫︎耐水性（たいすいせい）- Water resistance. ⚫︎撥水性（はっすいせい）- Water repellency. While not perfect synonyms, these words often appear with 防水 or in context similar to 防水.

⚫︎非防水（ひぼうすい）- Non-waterproof. ⚫︎水に弱い（みずによわい）- Weak to water.

このカメラは防水なので、雨の中でも使えます。 ・Translation: This camera is waterproof, so you can use it even in the rain. ・Explanation: This sentence explains the practical benefit of a waterproof camera.

そのテントは防水加工が施されている。 ・Translation: That tent has been treated with a waterproof coating. ・Explanation: This sentence describes the treatment of the tent to make it waterproof.

The word 防水 is a compound word formed from two kanji: 防（ぼう）, meaning "to prevent" or "to defend," and 水（すい）, meaning "water." Therefore, the literal meaning of 防水 is "preventing water."