1.
I messed up, I screwed up, I blew it
A casual exclamation acknowledging that one has made a significant mistake or blunder. Past tense of やらかす, almost always used in this past form to react to something that has already gone wrong.
I accidentally sent an important email to the wrong person. I really messed up.
やらかした is the past tense of やらかす (to mess up, to commit a blunder). The base form やらかす exists but is far less common in everyday speech — the past form やらかした is the standard way this word appears, used as a reactive exclamation after realizing a mistake.
Usage
- Self-directed: やらかした！ (I messed up!)
- About someone else: あいつ、またやらかしたよ (That guy screwed up again)
- The mistake is usually significant or embarrassing, not a trivial slip
Similar words
- やっちゃった: lighter tone, "oops" — suitable for minor mistakes
- しまった: "oh no" — a broader expression of regret
- やらかした: implies a bigger, more consequential blunder
Register
Casual. Not appropriate in formal or business settings. In polite speech, 失敗しました or ミスしました would be used instead.