To harm, injure, or damage something (such as property, reputation, health, or profit); similar in use to 'to impair' or 'to cause loss'.
長時間の残業は健康を損じるおそれがある。
Long hours of overtime may harm your health.
軽率な発言が彼の評判を損じてしまった。
A careless remark ended up damaging his reputation.
無駄な投資で会社の資産を損じた。
Wasteful investments damaged the company's assets.