gaichu - You think you know something, but it’s just a f***ing guess

You think you know something, but it’s just a f***ing guess and you’re not even sure.

I guessed the answer. It was right. Then I got it wrong. Gaichu.

I thought I knew the question. I just forgot the answer. Gaichu.

I said I knew the word. I just spelled it wrong. Gaichu.