Rén duō, zuǐ zá.*

人多嘴雜。

Lit [When there are] many people [gossiping], [their] mouths [get] tangled.

Fig Just let people say and think whatever they want; don't pay attention to gossip.

Note [This is often mistaken as a chengyu.]

Topics chengyu GOSSIP rénduō-zuǐzá