掉以轻心

掉以轻心 [diào yǐ qīng xīn]

1. ■ （对某种问题漫不经心， 不当回事） let down [lower] one's guard; be rid of sth. to lighten one's heart; dismiss the thought of the matter, etc. as unworthy of further attention; take [adopt] a casual attitude; take ... lightly; treat sth. lightly; trust sb. too lightly [readily; easily]; unwisely to believe in sb.'s words:

这场斗争是尖锐复杂的， 我们决不能掉以轻心。 This struggle is sharp and complex. We can never let down guard.