惘然若失 [－－－－]

Jyutping mong5 jin4 joek6 sat1
Pinyin wǎng rán ruò shī

Definitions (CC-CEDICT)
  1. lit. to be frustrated as though having lost sth (idiom)
  2. fig. to be at a loss
  3. perplexed
  4. frustrated
Definitions (Wiktionary)
  1. phrase, idiomatic
    to be at a loss; to be frustrated