張口結舌 [张－结－]

Jyutping zoeng1 hau2 git3 sit3
Pinyin zhāng kǒu jié shé

Definitions (CC-CEDICT)
  1. agape and tongue-tied (idiom); at a loss for words
  2. gaping and speechless
Definitions (Wiktionary)
  1. phrase, idiomatic
    at a loss for words
    (syn.) 喙窒舌