1. 愚蠢的错误；疏忽；失误
    A blunder is a stupid or careless mistake.

    e.g. I think he made a tactical blunder by announcing it so far ahead of time.
           我认为他在时机远未成熟时就把这事说了出去是一种失策。

2. 犯愚蠢的错误；失误
    If you blunder, you make a stupid or careless mistake.

blunder

    e.g. No doubt I had blundered again...
           无疑，我又犯了一个愚蠢的错误。
    e.g. You're a blundering fool.
           你是一个大笨蛋。

3. 不慎陷入，误打误撞地进入（危险或困难的境地）
    If you blunder into a dangerous or difficult situation, you get involved in it by mistake.

blunder

    e.g. People wanted to know how they had blundered into war, and how to avoid it in future.
           人们想知道他们是怎样稀里糊涂地陷入战争的，以及日后该如何避免重蹈覆辙。

4. 跌跌撞撞；慌乱地走
    If you blunder somewhere, you move there in a clumsy and careless way.

    e.g. He had blundered into the table, upsetting the flowers.
           他不小心撞到了桌子，把花打翻了。