Select the most appropriate meaning of the given idiom.

Be at a loss for words

Not know what to say

The most appropriate meaning of the idiom "be at a loss for words" is >not know what to say.<

It means to be so surprised, shocked, or overwhelmed that you can't think of anything to say. The idiom is often used to describe someone who is trying to express their emotions but is unable to find the right words.

The other options are not correct.

• Habituated to using difficult words: This does not mean not knowing what to say.
• Not aware of the language: This does not mean not knowing what to say.
• Lost the urge to speak: This does not mean not knowing what to say.