テストは、よくなかった。

これはいい本（ほん）です。

いい？

昨日（きのう）は、よかったです。

これは、いい映画（えいが）だ。

いいです。

これもいい本（ほん）です。

彼女（かのじょ）も、いい人（ひと）です。

明日（あした）もいいです。

これはいいです。

これはいい音（おと）だ。

これはよくない。

<div class='writeup-body'>いい is an adjective that means 'good' in Japanese. It can be a little bit difficult to use at first, as it conjugates differently to other い-Adjectives.<ul class='writeup-examples--holder'><li class='writeup-example'><div class='writeup-example--japanese'>これはいい映画（えいが）だ。</div><div class='writeup-example--english'>This is a good movie.</div></li><li class='writeup-example'><div class='writeup-example--japanese'>これは良（よ）くない。</div><div class='writeup-example--english'>This is not good.</div></li><li class='writeup-example'><div class='writeup-example--japanese'>昨日（きのう）の天気（てんき）はよかった。</div><div class='writeup-example--english'>Yesterday's weather was good.</div></li><li class='writeup-example'><div class='writeup-example--japanese'>昨日（きのう）の天気（てんき）はよくなかった。</div><div class='writeup-example--english'>Yesterday's weather was not good.</div></li></ul>In these sentences, we can see that the first い in いい changes to よ, depending on the form. This is unique to いい, and does not happen with other adjectives. いい can sometimes be seen as 良（よ）い, in these cases, the kanji is likely to be read as よい, and not いい. There is technically no difference between these two meanings, but よい does sound more formal/old-fashioned.<ul class='writeup-examples--holder'><li class='writeup-example'><div class='writeup-example--japanese'>これはいい車（くるま）だ。</div><div class='writeup-example--english'>This is a good car.</div></li> <li class='writeup-example'><div class='writeup-example--japanese'>これも良（よ）い。</div><div class='writeup-example--english'>This is also splendid. ('Splendid' is similar to the nuance that よい gives いい)</div></li></ul><div class='writeup-caution'><div class='caution-header'>Caution</div>When used as an adverb, よく should not be confused as a conjugation of いい. よく has several possible kanji that it may stem from, and means frequently/often/well.</div></div>

Grammar Info

良(い)い

い-Adjective meaning 'good'