Correct

小大人

/ xiǎo dà rén /
Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/小大人-Chinese-idioms-Cchatty-8961c623-1a73-4c02-9d14-9a682e3849a8-1612776971.jpg

Collocation

1
像小大人似的
2
像个小大人

Definition

小大人

Literally means:

little big man

Actually means:

It refers to a small child who talks or behaves like an adult.

个头长得不大,但说话做事带有某些成年人特点的小孩子。

Example

Used as subject or object. (作主语、宾语)
1
Háizi
孩子
zhǐbuguò
只不过
zhège
这个
háizi
孩子
zhǐbuguò
只不过
men
我们
de
érzi
儿子
suì
  
,
dàn
shuō
huà
lái
dào
xiàng
xiǎo
ren
大人
  

The child is only a year older than our son, but he speaks like a little man.

2
Yóu
由于
ma
妈妈
de
zǎo
  
,
liù
六七
suì
biàn
便
xiàng
xiǎo
ren
大人
shìde
似的
bāng
ba
爸爸
mǎi
cài
  
shāofàn
烧饭
  
zuò
jiā
家务
le
  

Because her mother died early, she was six or seven years old like a small man to help her father buy food, cook, do housework.

3
Biè
kàn
zài
zhè
qún
háizi
孩子
zhōng
zi
个子
zuì
xiǎo
  
,
shuōhuà
说话
bànshì
办事
què
xiàng
xiǎo
ren
大人
  

Don't look at her as the youngest of these children, but she can talk and act like a little man.