Lack of Understanding

in a very nervous or frustrating state of mind in face of a problem or situation one knows very little or nothing about

He's out of his depth in that advanced physics class.

said when one does not have a definite answer to a particular question, similar to the questioner

When will the project be completed?Your guess is as good as mine.

to fail to understand or interpret or understand something correctly

I think you've got the wrong end of the stick.I didn't mean it that way.

to have no information regarding a particular subject

I don't know beans about car engines, so I rely on the mechanic to explain what's wrong.

used when one is incapable of understanding or remembering a particular thing

He couldn't remember the name of the movie for the life of him.

someone or something one knows very little or nothing about

The workings of the stock market are a closed book to me – I don't understand how it works.

used to describe something that is complicated due to not being clearly described or shown

His instructions for assembling the furniture were clear as mud; I had to figure it out on my own.

the limits of human knowledge or understanding, representing areas that remain unknown or unexplored

For scientists, the nature of consciousness remains the final frontier of human understanding.

confused and unable to think clearly

I've been so busy lately that I'm in a fog when it comes to my schedule.

to make an attempt to understand someone or something that is puzzling

I can't make heads or tails of this manual; it's so poorly written.