jiā chǒu bù kě wài chuán
lit. family shames must not be spread abroad (idiom); fig. don't wash your dirty linen in public
jiā chǒu bù kě wài chuán , liú yán qiē mò qīng xìn
Don't spread abroad the shame of the family, don't believe rumors lightly (common expression); Don't wash your dirty linen in public, don't listen to others' gossip.