noun
undeserved good luck; dumb luck; luck of the devil
Refers to luck that seems undeserved or almost supernatural, often with a negative or envious tone. Used when someone escapes trouble or succeeds without apparent merit.
彼は悪運が強くて、いつもピンチを切り抜ける。
He has the devil's own luck and always gets out of tight spots.
あの男の悪運には呆れるよ。
I'm amazed at that guy's dumb luck.
noun
Less common than the 'undeserved good luck' sense. Can be ambiguous; context usually clarifies whether it means good luck that seems undeserved or actual misfortune.
悪運に見舞われて、事業に失敗した。
Struck by bad luck, his business failed.