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thoughtlessly; recklessly; rashly; indiscriminately; indiscreetly; at random
excessively; unreasonably; immoderately; absurdly
無闇に人を批判するべきではありません。
You shouldn't criticize recklessly.
無闇に手を出すと必ず失敗します。
If you act recklessly, you'll fail.
無闇に人の話を信じてはいけません。
You shouldn't believe blindly.