망연자실이 · 망연자실을
being stunned and at a loss, dazed with shock
Example
갑작스러운 사고 소식에 가족들은 망연자실했어요.
The family was stunned by the sudden news of the accident.
Word parts
망 blank+연 -ly+자 self+실 lose
Literally 'blankly losing oneself' — too shocked to think.
Good to know
Usually 망연자실하다 or 망연자실한 표정, describing a reaction to sudden loss or disaster.