渾身是口也說不清

húnshēnshìkǒuyěshuōbùqīng ㄏㄨㄣˊ ㄕㄣ ㄕˋ ㄎㄡˇ ㄧㄝˇ ㄕㄨㄛ ㄅㄨˋ ㄑㄧㄥ

    • unable to clear oneself or explain however hard one tries

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
Even with a mouth all over your body you couldn't explain it
Meaning
Said when one cannot clear oneself or explain a situation however hard one tries.

Sources