還沒長完
這一族直接就是核心畫面：生物體還在成長途中，還沒到成熟的那個階段。
not fully grown · adjective · C2
Not fully formed or fully grown yet, for example a young plant or animal.
未成熟
核心畫面
A fruit still hard and green on the branch — it has not finished growing into what it is meant to become.
一顆還掛在樹上、硬硬綠綠的果子。它不是壞掉，也不是有問題，它只是還沒長完——時間還沒到，該有的形狀、該有的甜度都還沒…更多收起
一顆還掛在樹上、硬硬綠綠的果子。它不是壞掉，也不是有問題，它只是還沒長完——時間還沒到，該有的形狀、該有的甜度都還沒到位。immature 這個字整體都罩在這個「還沒長完」的畫面下，差別只在講的是植物、動物，還是一個人的心智。From the word’s history
From Latin immaturus = in- 'not' + maturus 'ripe, timely', the same maturus behind mature — so the word literally means 'not yet ripe'.
來自拉丁文 immaturus：in-（不）＋ maturus（成熟的、時機到了的）。maturus 也是 mature 的來源，本來就是講果實熟了、時候到了。所以 immature 字面上就是「還沒熟」——農作物的畫面直接留在字裡，後來才被拿去講人。
Wiktionary (immature, Latin immaturus, maturus)
Two branches
心智還沒長完
把樹上那顆青果的畫面搬到人的心智上：身體已經長大了，但反應和想法還停在更小的年紀。
childish behavior · adjective · C2
Behaving or thinking in a way that is usual for someone much younger, so people feel you are not as grown-up as they expect.
幼稚
原始詞典資料4 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
immatureadj/ɪməˈtjʊə(ɹ)/
- 1
archaicOccurring before the proper time; untimely, premature (especially of death).
- And thou also canst best account for the causes of her immature death […].
- 2
Not fully formed or developed; not grown.
- 3
Childish in behavior; juvenile.
- You're only young once, but you can be immature the rest of your life.
- The man was immature for throwing a tantrum.
immaturenoun/ɪməˈtjʊə(ɹ)/
- 1
An immature member of a species.
- There are many genera and even families of Brachypylina for which immatures are not yet known, and thus numerous examples of adult convergence and misclassification remain to be revealed: such is the case with Hypozetes.
- While on a walk the next morning I found what looked like a patch of old growth habitat - perhaps somewhere the fires had missed - and to my astonishment saw a female Red-lored Whistler accompanied by an immature.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。