What is the difference between 良い and いい?


Consider the following:

> 良い _yoi_ — 良く _yoku_
>
> いい _ii_ — よく _yoku_

When typing いい, IME offers 良い in the lookup table. It makes me wonder whether
いい is just an alias of 良い but it is pronounced differently only in the
dictionary form.

What is the difference between 良い and いい?




良い can be read as both いい and よい. 良{よ}い is more formal than いい. But they are
very similar words, and they are sometimes safely interchangeable. For
example, the following words are the same and both mean "good boy/girl".

いい子{こ}  
良{よ}い子{こ}

Sometimes, いい cannot be replaced with 良い in casual language. For instance, in
the Japanese version of Facebook, you call the "Like" button, the "いいね"
button. If you replace it to "良いね", it would be a little bit strange because
いいね is a casual word, and 良い is somewhat formal. They should go together.




良い can be read as both いい and よい. 良{よ}い is more formal than いい. But they are
very similar words, and they are sometimes safely interchangeable. For
example, the following words are the same and both mean "good boy/girl".

いい子{こ}  
良{よ}い子{こ}

Sometimes, いい cannot be replaced with 良い in casual language. For instance, in
the Japanese version of Facebook, you call the "Like" button, the "いいね"
button. If you replace it to "良いね", it would be a little bit strange because
いいね is a casual word, and 良い is somewhat formal. They should go together.

