This phrase means 'you can do it'. It also means 'it is okay to do it'. It is a casual way to give permission.
Verb [て-form] + いいPrimary
This phrase means 'you can do it'. It also means 'it is okay to do it'. It is a casual way to give permission.
このケーキ、もう食べていいよ。
You can eat this cake now.
疲れてるなら、少し休んでいいから、無理しないでね。
If you're tired, it's okay to rest a little, so don't overdo it.
まだ宿題が終わっていないから、遊んでいいとは言われなかった。
Because I hadn't finished my homework yet, I wasn't told 'it's okay to play'.
上司に「この件は君に任せるから、好きにやっていい」と言われた。
My boss told me, 'I'm leaving this matter to you, so you can do it as you see fit'.
あ、そのゲーム、クリアしたからもうやっていいよ。
Oh, that game? I've already beaten it, so you can go ahead and play it.
This phrase is very casual. Use it with friends or family. You can use it with people younger than you. Do not use it with your boss or teacher. That would be rude.
This is a shorter way to say "〜てもいい" (temo ii). Both mean "it's okay to do something." This form is more direct. It is for quick talks with friends. It is different from asking for permission. This form gives permission.
Don't use this when you want to say "you can't do something." For example, don't say "tabete ikunai" to mean "you can't eat." Use other phrases like "tabete wa ikenai" or "tabecha dame" instead. These mean "you must not eat."
Contrasts with(3)
Less formal alternatives(1)
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