1.
good, fine
Of high quality or standard.
天気が良い。
The weather is good.
この店は料理が良い。
This restaurant has good food.
景色が良いですね。
The scenery is beautiful, isn't it?
彼は頭が良い。
He is smart.
体に良い食べ物を食べよう。
Let's eat food that's good for the body.
2.
all right, okay
Acceptable or permitted.
もう帰ってもよい。
You may go home now.
写真を撮ってもよいですか。
May I take a photo?
ここに座ってもよいですか。
May I sit here?
食べなくてもよい。
You don't have to eat it.
明日でもよいですか。
Is tomorrow okay?
良い is an i-adjective meaning "good" with an irregular form いい used in everyday speech.
FORMS:
- Dictionary: よい or いい (いい is more casual)
- Negative: よくない (NOT いくない)
- Past: よかった (NOT いかった)
- Adverb: よく (well, often)
GRAMMAR PATTERNS:
- 〜てもいい/よい: may ~, it's okay to ~
- 〜ばよかった: should have ~ (regret)
- 〜なくてもいい: don't have to ~
COMMON COLLOCATIONS:
- 天気がいい: good weather
- 頭がいい: smart
- 体にいい: good for the body
- 仲がいい: on good terms
- 運がいい: lucky
IMPORTANT:
Always conjugate from よ-, not い-. "It was good" = よかった, not いかった.