Weakness or feebleness in body, will, or character; lacking strength or resolve.
彼は緊張すると軟弱な態度をとってしまうことがある。
He sometimes acts weakly when he gets nervous.
軟弱な根拠ではその計画を進められない。
We can't proceed with that plan on such weak grounds.
台風で倒れた木は根の軟弱さが原因だった。
The trees that fell in the typhoon were caused by weak roots.