Correct

掉以轻心

/ diào yǐ qīng xīn /
Strokes

Definition

treat sth lightly/to lower one's guard

Example

Definition

let down/lower one's guard; be off one's guard; relax one's vigilance; take sth lightly; rest on one's oars

1
Duì
jiāotōng
交通
guī
规则
不可
diàoqīngxīn
掉以轻心
  

We must not ignore traffic regulations.

2
Hūnyīn
婚姻
shì
大事
不可
diàoqīngxīn
掉以轻心
  

Marriage is not something to be undertaken lightly.