Childish or immature; describing words, behavior, or thinking that seem juvenile relative to one's age or the situation.
そんな子供じみた言い訳は通用しないよ。
That childish excuse won't work.
彼の子供じみた振る舞いに、同僚は呆れている。
His childish behavior has exasperated his coworkers.
子供じみた嫉妬を見せるのはやめなさい。
Stop showing childish jealousy.
作品の一部には子供じみた表現もあるが、全体としては評価できる。
Some parts of the work are childlike, but overall it can be appreciated.