lǐ qū cí qióng

ㄌㄧˇ ㄑㄩㄘˊ ㄑㄩㄥˊ

Idiom

1to not have a leg to stand on

2lit. having presented a flawed argument, one has nothing further to add (idiom)

3fig. unable to provide a convincing argument to support one's position