形容詞 infantile:

1. indicating a lack of maturity
   同義詞：childish
2. of or relating to infants or infancy
3. being or befitting or characteristic of an infant

1. An adult or a young person who behaves in an infantile way.
   孩子氣的人行為表現(xiàn)出孩子氣的成年人或年輕人
2. Her unconscious looks wander to her husband with infantile dependency.
   帶著像嬰兒般的依賴她不由自主地把目光投向了她的丈夫。

in.fan.tile

adj.（形容詞）
Of or relating to infants or infancy.
嬰幼兒的：屬于嬰兒或嬰兒期的，或與之有關的
Displaying or suggesting a lack of maturity; extremely childish:
幼稚的：表露出或顯現(xiàn)出不成熟的；小孩子氣的：
例句：
infantile behavior; an infantile remark.
行為幼稚；幼稚的評論

來源：
Middle English infantil
中古英語 infantil
from Latin onfantolis
源自 拉丁語 onfantolis
from onf3ns onfant- [infant] * see infant
源自 onf3ns onfant- [嬰兒] *參見 infant