He mixes up words, so his letter is full of blunders.

If animals could speak, the dog would be a blundering outspoken fellow; but the cat would have the rare grace of never saying a word too much.

Yanni knows how to exploit their blunders.

What was she doing when she made that blunder?

He was guilty of a blunder.

As a result of his carelessness, he made a serious blunder.

What a blunder!

You should leave me cool; otherwise, I will say a possible blunder!

The grandmaster blundered his queen.

A-ha-ha-ha! What a blunder!