furigana: いい・よい
romaji: ii or yoi
Meaning: good
Level: JLPT N5
Writing
| Kanji | Meaning | Onyomi | Kunyomi | JLPT |
| 良 | good | RYOU | yo(i) | – |
| い | hiragana i | 5 |
Grammar: i-adjective
| Form | Kanji | Furigana |
Romaji | JLPT |
| plain form | 良い | よい・いい | yoi / ii | 5 |
| past | 良かった | よかった | yokatta | – |
| negation | 良くない | よくない | yokunai | – |
| past negation | 良くなかった | よくなかった | yokunakatta | – |
| sa form | 良さ | よさ | yosa | – |
| sou form | 良さそう | よさそう | yosasou | – |
Be careful since there is an exception on the sou-form. It is not yosou but yosasou (for easier pronunciation).
Examples
| Kanji | 私の父はとても良い人です。 |
| Furigana | わたしのちちはとてもいいひとです。 |
| Romaji | watashi no chichi wa totemo ii hito desu. |
| English | My father is a very good person |
Vocabulary
Synonym
| Kanji | Furigana |
Romaji | Meaning | JLPT |
| – |
Opposite
| Kanji | Furigana |
Romaji | Meaning | JLPT |
| 悪い | わるい | warui | bad | 5 |
Related words
| Kanji | Furigana |
Romaji | Meaning | JLPT |
| – | ||||
| – |
NIHONGO ICHIBAN 
よい・いい
whether for the past can use いかった？also negation etc.
This is a very good question. ii / yoi is a little bit irregular and all other forms than the plain form are only made with yo- NOT i-.