source: Lion Takes A Misstep GIF by Kolafie | Gfycat

a stupid or careless mistake.

(不注意で愚かな)大失策, 不覚, 不手際

verb no object

make a stupid or careless mistake; act or speak clumsily:

(不注意のせいで)大失敗する; しどろもどろに言う(on)

e.g. the mayor and the City Council have blundered in an ill-advised campaign

e.g. I blundered on in my explanation

e.g. (as adjective blundering) : blundering actors.

move clumsily or as if unable to see:

〖blunder＋副詞〗 (目が見えないかのように)恐る恐る進む; ぶつかる, つまずく; (困難な状況に)陥る (!〖副詞〗は方向の表現)

e.g. we were blundering around in the darkness.

blunderer |ˈblənd(ə)rər| noun

blunderingly adverb

Middle English: probably of Scandinavian origin and related to blind.