Not ready yet. We use `unripe` mostly about fruit and grain that has not finished growing sweet and soft — an unripe banana is still green and hard, an unripe mango makes your mouth pucker. The word carries a small judgement with it: unripe fruit is not just young, it is not good to eat *yet*. That 'yet' matters. Nobody says an unripe apple is bad the way rotten fruit is bad; they mean you came too early. Farmers also talk about unripe grain — wheat or rice still green in the field, too soft to harvest. People stretch it to people and plans, though this feels literary rather than everyday. An unripe idea is one that needs more time before you show it to anyone. You will meet this stretched use in writing more than in speech; if a Taiwanese student says it in conversation, it sounds a little poetic, which may be exactly what you want or may not. One quiet thing about how it is really used: in Taiwan we eat plenty of fruit deliberately unripe — green mango with plum powder, hard guava — and English does not really have a friendly word for that. `Unripe` still sounds like a complaint even when you are happy about it. If you mean it as a good thing you usually have to say so: 'I like green mango when it's still unripe and sour.'

未熟的、還沒熟的（水果）；青澀的。台灣講水果多半直接說「還沒熟」或「青的」，「未熟」比較書面。用在人或想法上時是「不成熟、青澀」。