bad; poor; defective — of low quality, faulty, or inferior
工場で不良品が大量に発生した。
A large number of defective products were produced at the factory.
不良債権の処理には時間がかかる。
Handling nonperforming (bad) loans takes time.
この機械は古くて調子が不良だ。
This machine is old and in poor working condition.
a delinquent; hooligan — a person, often a young person, who engages in antisocial or delinquent behavior
学校で不良と呼ばれる生徒がトラブルを起こした。
A student labeled as a delinquent caused trouble at school.
あの地域では不良グループの問題が深刻だ。
Problems with delinquent gangs are serious in that area.
親は子どもの不良行為を心配している。
Parents are worried about their child's delinquent behavior.