風邪: reading and writing

Question

Why do we write かぜ (cold) as 風邪, not just 風?

The second kanji (邪) is left unread, so why isn't it redundant?

Perhaps, that's to make sure cold doesn't sound like wind. But then why don't we read it in the word 風邪 (かぜ)?

Answer 1

かぜ in the context of this question has two (related) meanings.

• The meaning wind is written as 風, because that's how you write wind in Chinese.
• The meaning cold (sickness) is written as 風邪, because that's how you write cold (sickness) in Chinese (or more specifically, Traditional Chinese medicine).

The second kanji (邪) is left unread

This is not the correct way to think about it. All non-Chinese readings of kanji are basically Japanese translations of Chinese words. In principle, any kanji or a string of multiple kanji can be read with a Japanese translation that is etymologically distinct from the Chinese word the kanji represents.

• A Japanese translation-reading for a single character is called kun'yomi. Hence, かぜ is a kun'yomi for the character 風.
• A Japanese translation-reading for multiple characters is called jukujikun (if these readings are established readings). Hence, かぜ is a jukujikun for the kanji string 風邪.
  • The character representation of a jukujikun word does not necessarily have a morpheme correspondence between the Chinese characters and Japanese morphemes, so you cannot decompose 風邪 into Japanese morphemes. Hence, 風 in 風邪 is not read as かぜ, and 邪 is not "unread".