be lost for words
US /bi lɔst fɔr wɜrdz/
UK /bi lɔst fɔr wɜrdz/

1.
kehilangan kata-kata, terdiam
to be so surprised, confused, or emotional that you cannot think of anything to say
:
•
When she saw the surprise party, she was completely lost for words.
Ketika dia melihat pesta kejutan itu, dia benar-benar kehilangan kata-kata.
•
His rude comment left me lost for words.
Komentar kasarnya membuat saya kehilangan kata-kata.