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brittle; fragile; weak; frail
tender-hearted; sentimental; easily moved
長年の風化でもろくなった石垣が崩れ落ちた。
The stone wall, weakened by years of weathering, crumbled.
彼は外見と違い精神的にもろい面がある。
Contrary to his appearance, he has a mentally fragile side.
もろい地盤の上に高層ビルを建てるのは危険だ。
Building a high-rise on fragile ground is dangerous.