安心 (anshin) means 'relief' or 'peace of mind.' It describes the feeling of being free from worry or fear. It can be used as a noun or as a な-adjective (安心な). For example, '無事だと聞いて安心しました' (I was relieved to hear you were safe).

「安心」は、心配がなく落ち着くことです。例：「安心する」