infantile

形容词 infantile:

1. indicating a lack of maturity
   同义词：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.
   孩子气的人行为表现出孩子气的成年人或年轻人
2. Her unconscious looks wander to her husband with infantile dependency.
   带著像婴儿般的依赖她不由自主地把目光投向了她的丈夫。

in.fan.tile

adj.（形容词）
Of or relating to infants or infancy.
婴幼儿的：属于婴儿或婴儿期的，或与之有关的
Displaying or suggesting a lack of maturity; extremely childish:
幼稚的：表露出或显现出不成熟的；小孩子气的：
例句：
infantile behavior; an infantile remark.
行为幼稚；幼稚的评论

来源：
Middle English infantil
中古英语 infantil
from Latin onfantolis
源自 拉丁语 onfantolis
from onf3ns onfant- [infant] * see infant
源自 onf3ns onfant- [婴儿] *参见 infant