to not know what to do or say.

He won't accept financial help from me so I'm at a loss to know what to do. (usually + to do something)

For once I found myself completely at a loss for words. (= I did not know what to say)

• cotton-picking
• cotton to
• cotton to someone
• cotton to something
• couch potato
• cough up
• cough up something
• could do something in sleep
• could do something in their sleep
• could do something standing on head
• could do something standing on your head
• could do something with eyes closed
• could do something with eyes shut
• could do something with one arm tied behind back
• could do something with one arm tied behind their back
• could do something with one hand tied behind back
• could do something with one hand tied behind their back
• could do something with their eyes closed
• could do something with their eyes shut
• could do with
• could do with one arm tied behind back
• could do with one arm tied behind their back
• could do with one hand tied behind back
• could do with one hand tied behind their back
• could do with something