The act of using something improperly or excessively — misuse, abuse, or misappropriation (of power, drugs, resources, etc.).
薬を乱用すると健康を害することが多い。
Abusing drugs often damages your health.
その権力の乱用は社会的に大きな問題だ。
The abuse of that power is a major social problem.
個人情報の乱用を防ぐための対策が必要だ。
Measures are needed to prevent the misuse of personal information.