When your mind is a blank/goes blank, you cannot remember a particular thing, or you cannot remember anything.


His mind went blank in the exam.

Suddenly my mind went blank ( = I could not remember anything).

My heart began to race and my mind went blank.

I tried to remember her name, but my mind was a complete blank/went completely blank.

Her mind went blank.

I should know the answer, but my mind’s a blank.

This caught her off guard, then her mind went temporarily blank.